Carbon materials comprising enhanced electrochemical properties

ABSTRACT

The present application is directed to carbon materials comprising an optimized pore structure. The carbon materials comprise enhanced electrochemical properties and find utility in any number of electrical devices, for example, as electrode material in ultracapacitors. Methods for making the disclosed carbon materials are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to U.S. application Ser. No.13/336,975, filed Dec. 23, 2011; which claims the benefit under 35U.S.C. §119(e) of U.S. Provisional Patent Application No. 61/427,649filed on Dec. 28, 2010, the contents of which are hereby incorporated intheir entirety by reference.

BACKGROUND

Technical Field

The present invention generally relates to carbon materials comprisingan optimized pore structure, methods for making the same and devicescontaining the same.

Description of the Related Art

Activated carbon is commonly employed in electrical storage anddistribution devices. The high surface area, conductivity and porosityof activated carbon allows for the design of electrical devices havinghigher energy density than devices employing other materials. Electricdouble-layer capacitors (EDLCs or “ultracapacitors”) are an example ofsuch devices. EDLCs often have electrodes prepared from an activatedcarbon material and a suitable electrolyte, and have an extremely highenergy density compared to more common capacitors. Typical uses forEDLCs include energy storage and distribution in devices requiring shortbursts of power for data transmissions, or peak-power functions such aswireless modems, mobile phones, digital cameras and other hand-heldelectronic devices. EDLCs are also commonly use in electric vehiclessuch as electric cars, trains, buses and the like.

Batteries are another common energy storage and distribution devicewhich often contain an activated carbon material (e.g., as anodematerial, current collector, or conductivity enhancer). For example,lithium/carbon batteries having a carbonaceous anode intercalated withlithium represent a promising energy storage device. Other types ofcarbon-containing batteries include lithium air batteries, which useporous carbon as the current collector for the air electrode, and leadacid batteries which often include carbon additives in either the anodeor cathode. Batteries are employed in any number of electronic devicesrequiring low current density electrical power (as compared to an EDLC'shigh current density).

One known limitation of EDLCs and carbon-based batteries is decreasedperformance at high-temperature, high voltage operation, repeatedcharge/discharge cycles and/or upon aging. This decreased performancehas been attributed, at least in part, to electrolyte impurity orimpurities in the carbon electrode itself, causing breakdown of theelectrode at the electrolyte/electrode interface. Thus, it has beensuggested that EDLCs and/or batteries comprising electrodes preparedfrom higher purity carbon materials could be operated at higher voltagesand for longer periods of time at higher temperatures than existingdevices.

In addition to purity, another known limitation of carbon-containingelectrical devices is the pore structure of the activated carbon itself.While activated carbon materials typically comprise high porosity, thepore size distribution is not optimized for use in electrical energystorage and distribution devices. Such optimization includes anidealized blend of both micropores and mesopores. An idealized pore sizedistribution is expected to maximize ion mobility (i.e., lowerresistance), increase power density and improve volumetric capacitanceof electrodes prepared from the optimized carbon materials.

Although the need for improved high purity carbon materials comprising apore structure optimized for high pulse power electrochemicalapplications has been recognized, such carbon materials are notcommercially available and no reported preparation method is capable ofyielding the same. One common method for producing high surface areaactivated carbon materials is to pyrolyze an existing carbon-containingmaterial (e.g., coconut fibers or tire rubber). This results in a charwith relatively low surface area which can subsequently beover-activated to produce a material with the surface area and porositynecessary for the desired application. Such an approach is inherentlylimited by the existing structure of the precursor material, andtypically results in a carbon material having an unoptimized porestructure and an ash content (e.g., metal impurities) of 1% or higher.

Activated carbon materials can also be prepared by chemical activation.For example, treatment of a carbon-containing material with an acid,base or salt (e.g., phosphoric acid, potassium hydroxide, sodiumhydroxide, zinc chloride, etc.) followed by heating results in anactivated carbon material. However, such chemical activation alsoproduces an activated carbon material not suitable for use in highperformance electrical devices.

Another approach for producing high surface area activated carbonmaterials is to prepare a synthetic polymer from carbon-containingorganic building blocks (e.g., a polymer gel). As with the existingorganic materials, the synthetically prepared polymers are pyrolyzed andactivated to produce an activated carbon material. In contrast to thetraditional approach described above, the intrinsic porosity of thesynthetically prepared polymer results in higher process yields becauseless material is lost during the activation step. However, known methodsfor preparing carbon materials from synthetic polymers produce carbonmaterials having unoptimized pore structures and unsuitable levels ofimpurities. Accordingly, electrodes prepared from these materialsdemonstrate unsuitable electrochemical properties.

While significant advances have been made in the field, there continuesto be a need in the art for improved high purity carbon materialscomprising an optimized pore structure for use in electrical energystorage devices, as well as for methods of making the same and devicescontaining the same. The present invention fulfills these needs andprovides further related advantages.

BRIEF SUMMARY

In general terms, the current invention is directed to novel carbonmaterials comprising an optimized pore structure. The optimized porestructure comprises a ratio of micropores to mesopores which increasesthe power density and provides for high ion mobility in electrodesprepared from the disclosed carbon materials. In addition, electrodesprepared from the disclosed carbon materials comprise low ionicresistance and high frequency response. The electrodes thus comprise ahigher power density and increased volumetric capacitance compared toelectrodes prepared from other carbon materials. The high purity of thecarbon materials also contributes to improving the operation, life spanand performance of any number of electrical storage and/or distributiondevices

Accordingly, the novel carbon materials find utility in any number ofelectrical energy storage devices, for example as electrode material inultracapacitors. Such devices containing the disclosed carbon materialsare useful in any number of applications, including applicationsrequiring high pulse power. Because of the unique properties of thedisclosed carbon materials, the devices are also expected to have higherdurability, and thus an increased life span, compared to other knowncarbon-containing electrochemical devices.

Accordingly, one embodiment of the present disclosure is directed to acarbon material comprising a pore structure, the pore structurecomprising micropores, mesopores and a total pore volume, wherein from40% to 90% of the total pore volume resides in micropores, from 10% to60% of the total pore volume resides in mesopores and less than 10% ofthe total pore volume resides in pores greater than 20 nm.

In other embodiments, from 40% to 50% of the total pore volume residesin micropores and from 50% to 60% of the total pore volume resides inmesopores. For example, in some embodiments, from 43% to 47% of thetotal pore volume resides in micropores and from 53% to 57% of the totalpore volume resides in mesopores. For example, in a specific embodiment,about 45% of the total pore volume resides in micropores and about 55%of the total pore volume resides in mesopores. In another embodiment,less than 5% of the total pore volume resides in pores greater than 20nm.

In still other embodiments, from 40% to 85% of the total pore volume ofthe carbon materials resides in micropores and from 15% to 40% of thetotal pore volume resides in mesopores. For example, in some embodimentsfrom 75% to 85% of the total pore volume resides in micropores and from15% to 25% of the total pore volume resides in mesopores. In otherembodiments from 65% to 75% of the total pore volume resides inmicropores and from 20% to 30% of the total pore volume resides inmesopores. In some specific embodiments, about 80% of the total porevolume resides in micropores and about 20% of the total pore volumeresides in mesopores. In other specific embodiments, about 70% of thetotal pore volume resides in micropores and about 30% of the total porevolume resides in mesopores.

In other embodiments, the disclosure provides a carbon materialcomprising a pore structure, the pore structure comprising micropores,mesopores and a total pore volume, wherein from 20% to 50% of the totalpore volume resides in micropores, from 50% to 80% of the total porevolume resides in mesopores and less than 10% of the total pore volumeresides in pores greater than 20 nm.

In some embodiments, from 20% to 40% of the total pore volume resides inmicropores and from 60% to 80% of the total pore volume resides inmesopores. In other embodiments, from 25% to 35% of the total porevolume resides in micropores and from 65% to 75% of the total porevolume resides in mesopores. For example, in some embodiments about 30%of the total pore volume resides in micropores and about 70% of thetotal pore volume resides in mesopores.

In still other embodiments of the foregoing carbon material, from 30% to50% of the total pore volume resides in micropores and from 50% to 70%of the total pore volume resides in mesopores. In other embodiments,from 35% to 45% of the total pore volume resides in micropores and from55% to 65% of the total pore volume resides in mesopores. For example,in some embodiments, about 40% of the total pore volume resides inmicropores and about 60% of the total pore volume resides in mesopores.

In certain variations of any of the above embodiments, less than 5% ofthe total pore volume resides in pores greater than 20 nm.

In other variations, the carbon material comprises a total impuritycontent of less than 500 ppm of elements having atomic numbers rangingfrom 11 to 92 as measured by proton induced x-ray emission. For example,the carbon material may comprise a total impurity content of less than200 ppm, less than 100 ppm or even less than 50 of elements havingatomic numbers ranging from 11 to 92 as measured by proton induced x-rayemission.

In other embodiments, the ash content of the carbon material is lessthan 0.03% as calculated from proton induced x-ray emission data, forexample, less than 0.01% or even less than 0.001% as calculated fromproton induced x-ray emission data.

In some embodiments, the carbon material comprises at least 95% carbonby weight as measured by combustion analysis and proton induced x-rayemission.

In yet other embodiments, the carbon material comprises less than 10 ppmiron as measured by proton induced x-ray emission, the carbon materialcomprises less than 3 ppm nickel as measured by proton induced x-rayemission, the carbon material comprises less than 30 ppm sulfur asmeasured by proton induced x-ray emission, the carbon material comprisesless than 1 ppm chromium as measured by proton induced x-ray emission,the carbon material comprises less than 1 ppm copper as measured byproton induced x-ray emission or the carbon material comprises less than1 ppm zinc as measured by proton induced x-ray emission.

In some certain embodiments, the carbon material comprises less than 100ppm sodium, less than 100 ppm silicon, less than 10 ppm sulfur, lessthan 25 ppm calcium, less than 10 ppm iron, less than 2 ppm nickel, lessthan 1 ppm copper, less than 1 ppm chromium, less than 50 ppm magnesium,less than 10 ppm aluminum, less than 25 ppm phosphorous, less than 5 ppmchlorine, less than 25 ppm potassium, less than 2 ppm titanium, lessthan 2 ppm manganese, less than 0.5 ppm cobalt and less than 5 ppm zincas measured by proton induced x-ray emission, and wherein all otherelements having atomic numbers ranging from 11 to 92 are undetected byproton induced x-ray emission.

In other embodiments, the carbon material comprises less than 50 ppmsodium, less than 50 ppm silicon, less than 30 ppm sulfur, less than 10ppm calcium, less than 10 ppm iron, less than 1 ppm nickel, less than 1ppm copper, less than 1 ppm chromium and less than 1 ppm zinc asmeasured by proton induced x-ray emission.

In some embodiments, the carbon material comprises less than 3.0%oxygen, less than 0.1% nitrogen and less than 0.5% hydrogen asdetermined by combustion analysis. For example, in further embodiments,the carbon material comprises less than 1.0% oxygen as determined bycombustion analysis.

In other embodiments, the carbon material comprises a pyrolyzed polymercryogel or the carbon material comprises an activated polymer cryogel.

In some specific embodiments, the carbon material comprises a BETspecific surface area of at least 500 m²/g, at least 1500 m²/g or atleast 2000 m²/g.

In other embodiments, the carbon material comprises a pore volume of atleast 0.60 cc/g or a pore volume of at least 1.00 cc/g. In otherembodiments, the carbon material comprises a pore volume of at least1.50 cc/g or a pore volume of at least 2.00 cc/g.

In yet other embodiments, the present disclosure provides an electrodecomprising a carbon material comprising a pore structure, the porestructure comprising micropores, mesopores and a total pore volume,wherein from 40% to 90% of the total pore volume resides in micropores,from 10% to 60% of the total pore volume resides in mesopores and lessthan 10% of the total pore volume resides in pores greater than 20 nm.

In certain embodiments of the disclosed electrode, the carbon materialcomprises a total impurity content of less than 500 ppm of elementshaving atomic numbers ranging from 11 to 92 as measured by protoninduced x-ray emission.

In still other embodiments, the present disclosure provides a devicecomprising a carbon material comprising a pore structure, the porestructure comprising micropores, mesopores and a total pore volume,wherein from 40% to 90% of the total pore volume resides in micropores,from 10% to 60% of the total pore volume resides in mesopores and lessthan 10% of the total pore volume resides in pores greater than 20 nm.

In some embodiments, the device is an electric double layer capacitorEDLC. In other embodiments, the device is a battery, for example alithium/carbon battery, zinc/carbon, lithium air battery or lead acidbattery. For example, in some embodiments the device is a lead/acidbattery comprising:

a) at least one positive electrode comprising a first active material inelectrical contact with a first current collector;

b) at least one negative electrode comprising a second active materialin electrical contact with a second current collector; and

c) an electrolyte;

wherein the positive electrode and the negative electrode are separatedby an inert porous separator, and wherein at least one of the first orsecond active materials comprises the carbon material.

In other certain embodiments, the device is an electric double layercapacitor (EDLC) device comprising:

a) a positive electrode and a negative electrode wherein each of thepositive and the negative electrodes comprise the carbon material;

b) an inert porous separator; and

c) an electrolyte;

wherein the positive electrode and the negative electrode are separatedby the inert porous separator.

In some aspects, the EDLC device comprises a gravimetric power of atleast 10 W/g, a volumetric power of at least 5 W/cc, a gravimetriccapacitance of at least 100 F/g or a volumetric capacitance of at least10.0 F/cc.

In other embodiments, the EDLC device comprises a gravimetriccapacitance of at least of at least 110 F/g as measured by constantcurrent discharge from 2.7 V to 0.1 V with a 5 second time constantemploying a 1.8 M solution of tetraethylammonium-tetrafluroroborate inacetonitrile electrolyte and a current density of 0.5 A/g. In stillother embodiments, the EDLC device comprises a volumetric capacitance ofat least of at least 15 F/cc as measured by constant current dischargefrom 2.7 V to 0.1 V with a 5 second time constant employing a 1.8 Msolution of tetraethylammonium-tetrafluroroborate in acetonitrileelectrolyte and a current density of 0.5 A/g.

In still other embodiments of the foregoing EDLC device, the EDLC devicecomprises a gravimetric capacitance of at least 13 F/cc as measured byconstant current discharge from 2.7 V to 0.1 V and with at least 0.24 Hzfrequency response and employing a 1.8 M solution oftetraethylammonium-tetrafluroroborate in acetonitrile electrolyte and acurrent density of 0.5 A/g. In some other embodiments, the EDLC devicecomprises a gravimetric capacitance of at least 17 F/cc as measured byconstant current discharge from 2.7 V to 0.1 V and with at least 0.24 Hzfrequency response and employing a 1.8 M solution oftetraethylammonium-tetrafluroroborate in acetonitrile electrolyte and acurrent density of 0.5 A/g.

In some embodiments of any of the foregoing devices, from 43% to 47% ofthe total pore volume resides in micropores and from 53% to 57% of thetotal pore volume resides in mesopores, and in other embodiments from83% to 77% of the total pore volume resides in micropores and from 17%to 23% of the total pore volume resides in mesopores.

In another variation of any of the foregoing devices, the carbonmaterial comprises a total impurity content of less than 500 ppm or lessthan 200 ppm, less than 100 ppm or even less than 50 ppm of elementshaving atomic numbers ranging from 11 to 92 as measured by protoninduced x-ray emission.

In other certain other embodiments of the foregoing devices, the ashcontent of the carbon material is less than 0.03%, for example less than0.01% or even less than 0.001% as calculated from proton induced x-rayemission data, while in other embodiments the carbon material comprisesat least 95% carbon as measured by combustion analysis and protoninduced x-ray emission.

In some specific embodiments of the foregoing devices, the carbonmaterial comprises less than 10 ppm iron as measured by proton inducedx-ray emission, less than 3 ppm nickel as measured by proton inducedx-ray emission, less than 30 ppm sulfur as measured by proton inducedx-ray emission, less than 1 ppm chromium as measured by proton inducedx-ray emission, less than 1 ppm copper as measured by proton inducedx-ray or less than 1 ppm zinc as measured by proton induced x-rayemission. In other embodiments, less than 5% of the total pore volumeresides in pores greater than 20 nm.

In other embodiments of the foregoing devices, the carbon materialcomprises an activated polymer cryogel. Other embodiments in includevariations wherein the carbon material comprises a BET specific surfacearea of at least 500 m²/g, at least 1500 m²/g or at least 2000 m²/g.

In yet another embodiment, the present disclosure provides a method formaking a carbon material comprising a pore structure, the pore structurecomprising micropores, mesopores and a total pore volume, wherein from40% to 90% of the total pore volume resides in micropores, from 10% to60% of the total pore volume resides in mesopores and less than 10% ofthe total pore volume resides in pores greater than 20 nm, wherein themethod comprises reacting one or more polymer precursors under acidicconditions in the presence of a volatile basic catalyst to obtain apolymer gel.

In certain embodiments of the foregoing method, from 43% to 47% of thetotal pore volume resides in micropores and from 53% to 57% of the totalpore volume resides in mesopores, and in other embodiments, from 83% to77% of the total pore volume resides in micropores and from 17% to 23%of the total pore volume resides in mesopores.

The disclosed method may also further comprise admixing the one or morepolymer precursors in a solvent comprising acetic acid and water. Othervariations include embodiments wherein the volatile basic catalystcomprises ammonium carbonate, ammonium bicarbonate, ammonium acetate,ammonium hydroxide, or combinations thereof. In another embodiment, theone or more polymer precursors comprise resorcinol and formaldehyde.

In some other further embodiments, the method further comprises:

-   -   (a) freeze drying the polymer gel to obtain a polymer cryogel;    -   (b) pyrolyzing the polymer cryogel to obtain a pyrolyzed        cryogel; and    -   (c) activating the pyrolyzed cryogel to obtain activated carbon        material.

These and other aspects of the invention will be apparent upon referenceto the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the figures, identical reference numbers identify similar elements.The sizes and relative positions of elements in the figures are notnecessarily drawn to scale and some of these elements are arbitrarilyenlarged and positioned to improve figure legibility. Further, theparticular shapes of the elements as drawn are not intended to conveyany information regarding the actual shape of the particular elements,and have been solely selected for ease of recognition in the figures.

FIG. 1 shows pore size distribution of two different batches of driedpolymer gel.

FIG. 2 is an overlay of the pore size distributions of pyrolyzed carbonmaterial and activated carbon material.

FIG. 3 is an overlay of pore size distribution by incremental porevolume of 3 carbon materials according to the present disclosure.

FIG. 4 demonstrates capacitance retention and stability over time forvarious carbon materials.

FIGS. 5A and 5 show B resistance of various carbon materials over time.

FIG. 6 is a Bode plot comparison of various carbon materials.

FIG. 7 shows pore size distribution of various carbon materials.

FIG. 8 shows two different batches of carbon material according to thepresent disclosure.

FIG. 9 is an overlay of the pore size distribution of various carbonmaterials.

FIG. 10 illustrates a prototype capacitor cell constructed to test thecarbon materials.

FIG. 11 depicts 30 minute leakage current values at four differentvoltages for the two test capacitors.

FIG. 12 is a graph of constant current discharges of the prototypecapacitors containing the disclosed carbon material.

FIG. 13A is a complex plane representation of impedance data from thecapacitor fabricated using the disclosed carbon material and organicelectrolyte.

FIG. 13B is a Bode representation of impedance data for the capacitorcontaining the disclosed carbon material and organic electrolyte.

FIG. 13C presents impedance data represented as a series-RC circuit.

FIG. 14 shows experimentally determined energy—power relationship for atest capacitor fabricated using the disclosed carbon materials andorganic electrolyte.

FIG. 15 is an overlay of the pore size distributions of flash frozen orslow frozen dried polymer gels.

FIG. 16 is an overlay of the pore size distribution of carbon materialsprepared from flash frozen or slow frozen dried gels.

FIG. 17 is a graph showing activation weight loss and surface areas forliquid nitrogen (LN) or shelf frozen (SF) polymer gels.

FIG. 18 shows pore size distribution of exemplary carbon samples.

FIG. 19 is a graph showing pore size distribution of dried gel samples.

FIG. 20 presents pore size distributions of various carbon samples.

DETAILED DESCRIPTION

In the following description, certain specific details are set forth inorder to provide a thorough understanding of various embodiments.However, one skilled in the art will understand that the invention maybe practiced without these details. In other instances, well-knownstructures have not been shown or described in detail to avoidunnecessarily obscuring descriptions of the embodiments. Unless thecontext requires otherwise, throughout the specification and claimswhich follow, the word “comprise” and variations thereof, such as,“comprises” and “comprising” are to be construed in an open, inclusivesense, that is, as “including, but not limited to.” Further, headingsprovided herein are for convenience only and do not interpret the scopeor meaning of the claimed invention.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment. Thus, the appearances of the phrases “in one embodiment” or“in an embodiment” in various places throughout this specification arenot necessarily all referring to the same embodiment. Furthermore, theparticular features, structures, or characteristics may be combined inany suitable manner in one or more embodiments. Also, as used in thisspecification and the appended claims, the singular forms “a,” “an,” and“the” include plural referents unless the content clearly dictatesotherwise. It should also be noted that the term “or” is generallyemployed in its sense including “and/or” unless the content clearlydictates otherwise.

DEFINITIONS

As used herein, and unless the context dictates otherwise, the followingterms have the meanings as specified below.

“Carbon material” refers to a material or substance comprisedsubstantially of carbon. Carbon materials include ultrapure as well asamorphous and crystalline carbon materials. Examples of carbon materialsinclude, but are not limited to, activated carbon, pyrolyzed driedpolymer gels, pyrolyzed polymer cryogels, pyrolyzed polymer xerogels,pyrolyzed polymer aerogels, activated dried polymer gels, activatedpolymer cryogels, activated polymer xerogels, activated polymer aerogelsand the like.

“Amorphous” refers to a material, for example an amorphous carbonmaterial, whose constituent atoms, molecules, or ions are arrangedrandomly without a regular repeating pattern. Amorphous materials mayhave some localized crystallinity (i.e., regularity) but lack long-rangeorder of the positions of the atoms. Pyrolyzed and/or activated carbonmaterials are generally amorphous.

“Crystalline” refers to a material whose constituent atoms, molecules,or ions are arranged in an orderly repeating pattern. Examples ofcrystalline carbon materials include, but are not limited to, diamondand graphene.

“Synthetic” refers to a substance which has been prepared by chemicalmeans rather than from a natural source. For example, a synthetic carbonmaterial is one which is synthesized from precursor materials and is notisolated from natural sources.

“Impurity” or “impurity element” refers to an undesired foreignsubstance (e.g., a chemical element) within a material which differsfrom the chemical composition of the base material. For example, animpurity in a carbon material refers to any element or combination ofelements, other than carbon, which is present in the carbon material.Impurity levels are typically expressed in parts per million (ppm).

“PIXE impurity” or “PIXE element” is any impurity element having anatomic number ranging from 11 to 92 (i.e., from sodium to uranium). Thephrases “total PIXE impurity content” and “total PIXE impurity level”both refer to the sum of all PIXE impurities present in a sample, forexample, a polymer gel or a carbon material. PIXE impurityconcentrations and identities may be determined by proton induced x-rayemission (PIXE).

“Ultrapure” refers to a substance having a total PIXE impurity contentof less than 0.050%. For example, an “ultrapure carbon material” is acarbon material having a total PIXE impurity content of less than 0.050%(i.e., 500 ppm).

“Ash content” refers to the nonvolatile inorganic matter which remainsafter subjecting a substance to a high decomposition temperature.Herein, the ash content of a carbon material is calculated from thetotal PIXE impurity content as measured by proton induced x-rayemission, assuming that nonvolatile elements are completely converted toexpected combustion products (i.e., oxides).

“Polymer” refers to a macromolecule comprised of two or more structuralrepeating units.

“Synthetic polymer precursor material” or “polymer precursor” refers tocompounds used in the preparation of a synthetic polymer. Examples ofpolymer precursors that can be used in certain embodiments of thepreparations disclosed herein include, but are not limited to, aldehydes(i.e., HC(═O)R, where R is an organic group), such as for example,methanal (formaldehyde); ethanal (acetaldehyde); propanal(propionaldehyde); butanal (butyraldehyde); glucose; benzaldehyde andcinnamaldehyde. Other exemplary polymer precursors include, but are notlimited to, phenolic compounds such as phenol and polyhydroxy benzenes,such as dihydroxy or trihydroxy benzenes, for example, resorcinol (i.e.,1,3-dihydroxy benzene), catechol, hydroquinone, and phloroglucinol.Mixtures of two or more polyhydroxy benzenes are also contemplatedwithin the meaning of polymer precursor.

“Monolithic” refers to a solid, three-dimensional structure that is notparticulate in nature.

“Sol” refers to a colloidal suspension of precursor particles (e.g.,polymer precursors), and the term “gel” refers to a wetthree-dimensional porous network obtained by condensation or reaction ofthe precursor particles.

“Polymer gel” refers to a gel in which the network component is apolymer; generally a polymer gel is a wet (aqueous or non-aqueous based)three-dimensional structure comprised of a polymer formed from syntheticprecursors or polymer precursors.

“Sol gel” refers to a sub-class of polymer gel where the polymer is acolloidal suspension that forms a wet three-dimensional porous networkobtained by reaction of the polymer precursors.

“Polymer hydrogel” or “hydrogel” refers to a subclass of polymer gel orgel wherein the solvent for the synthetic precursors or monomers iswater or mixtures of water and one or more water-miscible solvent.

“RF polymer hydrogel” refers to a sub-class of polymer gel wherein thepolymer was formed from the catalyzed reaction of resorcinol andformaldehyde in water or mixtures of water and one or morewater-miscible solvent.

“Acid” refers to any substance that is capable of lowering the pH of asolution. Acids include Arrhenius, Brønsted and Lewis acids. A “solidacid” refers to a dried or granular compound that yields an acidicsolution when dissolved in a solvent. The term “acidic” means having theproperties of an acid.

“Base” refers to any substance that is capable of raising the pH of asolution. Bases include Arrhenius, Brønsted and Lewis bases. A “solidbase” refers to a dried or granular compound that yields basic solutionwhen dissolved in a solvent. The term “basic” means having theproperties of a base.

“Mixed solvent system” refers to a solvent system comprised of two ormore solvents, for example, two or more miscible solvents. Examples ofbinary solvent systems (i.e., containing two solvents) include, but arenot limited to: water and acetic acid; water and formic acid; water andpropionic acid; water and butyric acid and the like. Examples of ternarysolvent systems (i.e., containing three solvents) include, but are notlimited to: water, acetic acid, and ethanol; water, acetic acid andacetone; water, acetic acid, and formic acid; water, acetic acid, andpropionic acid; and the like. The present invention contemplates allmixed solvent systems comprising two or more solvents.

“Miscible” refers to the property of a mixture wherein the mixture formsa single phase over certain ranges of temperature, pressure, andcomposition.

“Catalyst” is a substance which alters the rate of a chemical reaction.Catalysts participate in a reaction in a cyclic fashion such that thecatalyst is cyclically regenerated. The present disclosure contemplatescatalysts which are sodium free. The catalyst used in the preparation ofa polymer gel (e.g., an ultrapure polymer gel) as described herein canbe any compound that facilitates the polymerization of the polymerprecursors to form an ultrapure polymer gel. A “volatile catalyst” is acatalyst which has a tendency to vaporize at or below atmosphericpressure. Exemplary volatile catalysts include, but are not limited to,ammoniums salts, such as ammonium bicarbonate, ammonium carbonate,ammonium hydroxide, and combinations thereof.

“Solvent” refers to a substance which dissolves or suspends reactants(e.g., ultrapure polymer precursors) and provides a medium in which areaction may occur. Examples of solvents useful in the preparation ofthe gels, ultrapure polymer gels, ultrapure synthetic carbon materialsand ultrapure synthetic amorphous carbon materials disclosed hereininclude, but are not limited to, water, alcohols and mixtures thereof.Exemplary alcohols include ethanol, t-butanol, methanol and mixturesthereof. Such solvents are useful for dissolution of the syntheticultrapure polymer precursor materials, for example dissolution of aphenolic or aldehyde compound. In addition, in some processes suchsolvents are employed for solvent exchange in a polymer hydrogel (priorto freezing and drying), wherein the solvent from the polymerization ofthe precursors, for example, resorcinol and formaldehyde, is exchangedfor a pure alcohol. In one embodiment of the present application, acryogel is prepared by a process that does not include solvent exchange.

“Dried gel” or “dried polymer gel” refers to a gel or polymer gel,respectively, from which the solvent, generally water, or mixture ofwater and one or more water-miscible solvents, has been substantiallyremoved.

“Pyrolyzed dried polymer gel” refers to a dried polymer gel which hasbeen pyrolyzed but not yet activated, while an “activated dried polymergel” refers to a dried polymer gel which has been activated.

“Cryogel” refers to a dried gel that has been dried by freeze drying.

“RF cryogel” refers to a dried gel that has been dried by freeze dryingwherein the gel was formed from the catalyzed reaction of resorcinol andformaldehyde.

“Pyrolyzed cryogel” is a cryogel that has been pyrolyzed but not yetactivated.

“Activated cryogel” is a cryogel which has been activated to obtainactivated carbon material.

“Xerogel” refers to a dried gel that has been dried by air drying, forexample, at or below atmospheric pressure.

“Pyrolyzed xerogel” is a xerogel that has been pyrolyzed but not yetactivated.

“Activated xerogel” is a xerogel which has been activated to obtainactivated carbon material.

“Aerogel” refers to a dried gel that has been dried by supercriticaldrying, for example, using supercritical carbon dioxide.

“Pyrolyzed aerogel” is an aerogel that has been pyrolyzed but not yetactivated.

“Activated aerogel” is an aerogel which has been activated to obtainactivated carbon material.

“Organic extraction solvent” refers to an organic solvent added to apolymer hydrogel after polymerization of the polymer precursors hasbegun, generally after polymerization of the polymer hydrogel iscomplete.

“Rapid multi-directional freezing” refers to the process of freezing apolymer gel by creating polymer gel particles from a monolithic polymergel, and subjecting said polymer gel particles to a suitably coldmedium. The cold medium can be, for example, liquid nitrogen, nitrogengas, or solid carbon dioxide. During rapid multi-directional freezingnucleation of ice dominates over ice crystal growth. The suitably coldmedium can be, for example, a gas, liquid, or solid with a temperaturebelow about −10° C. Alternatively, the suitably cold medium can be agas, liquid, or solid with a temperature below about −20° C.Alternatively, the suitably cold medium can be a gas, liquid, or solidwith a temperature below about −30° C.

“Activate” and “activation” each refer to the process of heating a rawmaterial or carbonized/pyrolyzed substance at an activation dwelltemperature during exposure to oxidizing atmospheres (e.g., carbondioxide, oxygen, steam or combinations thereof) to produce an“activated” substance (e.g., activated cryogel or activated carbonmaterial). The activation process generally results in a stripping awayof the surface of the particles, resulting in an increased surface area.Alternatively, activation can be accomplished by chemical means, forexample, by impregnation of carbon-containing precursor materials withchemicals such as acids like phosphoric acid or bases like potassiumhydroxide, sodium hydroxide or salts like zinc chloride, followed bycarbonization. “Activated” refers to a material or substance, forexample a carbon material, which has undergone the process ofactivation.

“Carbonizing”, “pyrolyzing”, “carbonization” and “pyrolysis” each referto the process of heating a carbon-containing substance at a pyrolysisdwell temperature in an inert atmosphere (e.g., argon, nitrogen orcombinations thereof) or in a vacuum such that the targeted materialcollected at the end of the process is primarily carbon. “Pyrolyzed”refers to a material or substance, for example a carbon material, whichhas undergone the process of pyrolysis.

“Dwell temperature” refers to the temperature of the furnace during theportion of a process which is reserved for maintaining a relativelyconstant temperature (i.e., neither increasing nor decreasing thetemperature). For example, the pyrolysis dwell temperature refers to therelatively constant temperature of the furnace during pyrolysis, and theactivation dwell temperature refers to the relatively constanttemperature of the furnace during activation.

“Pore” refers to an opening or depression in the surface, or a tunnel ina carbon material, such as for example activated carbon, pyrolyzed driedpolymer gels, pyrolyzed polymer cryogels, pyrolyzed polymer xerogels,pyrolyzed polymer aerogels, activated dried polymer gels, activatedpolymer cryogels, activated polymer xerogels, activated polymer aerogelsand the like. A pore can be a single tunnel or connected to othertunnels in a continuous network throughout the structure.

“Pore structure” refers to the layout of the surface of the internalpores within a carbon material, such as an activated carbon material.Components of the pore structure include pore size, pore volume, surfacearea, density, pore size distribution and pore length. Generally thepore structure of an activated carbon material comprises micropores andmesopores. For example, in certain embodiments the ratio of microporesto mesopores is optimized for enhanced electrochemical performance.

“Mesopore” generally refers to a pore having a diameter ranging from 2nanometers to 50 nanometers while the term “micropore” refers to a porehaving a diameter less than 2 nanometers.

“Surface area” refers to the total specific surface area of a substancemeasurable by the BET technique. Surface area is typically expressed inunits of m²/g. The BET (Brunauer/Emmett/Teller) technique employs aninert gas, for example nitrogen, to measure the amount of gas adsorbedon a material and is commonly used in the art to determine theaccessible surface area of materials.

“Connected” when used in reference to mesopores and micropores refers tothe spatial orientation of such pores.

“Effective length” refers to the portion of the length of the pore thatis of sufficient diameter such that it is available to accept salt ionsfrom the electrolyte.

“Electrode” refers to the positive or negative component of a cell(e.g., capacitor, battery, etc.) including the active material.Electrodes generally comprise one or more metal leads through whichelectricity enters or leaves the electrode.

“Binder” refers to a material capable of holding individual particles ofa substance (e.g., a carbon material) together such that after mixing abinder and the particles together the resulting mixture can be formedinto sheets, pellets, disks or other shapes. In certain embodiments, anelectrode may comprise the disclosed carbon materials and a binder.Non-exclusive examples of binders include fluoro polymers, such as, forexample, PTFE (polytetrafluoroethylene, Teflon), PFA (perfluoroalkoxypolymer resin, also known as Teflon), FEP (fluorinated ethylenepropylene, also known as Teflon), ETFE (polyethylenetetrafluoroethylene,sold as Tefzel and Fluon), PVF (polyvinyl fluoride, sold as Tedlar),ECTFE (polyethylenechlorotrifluoroethylene, sold as Halar), PVDF(polyvinylidene fluoride, sold as Kynar), PCTFE(polychlorotrifluoroethylene, sold as Kel-F and CTFE), trifluoroethanoland combinations thereof.

“Inert” refers to a material that is not active in the electrolyte of anelectrical energy storage device, that is it does not absorb asignificant amount of ions or change chemically, e.g., degrade.

“Conductive” refers to the ability of a material to conduct electronsthrough transmission of loosely held valence electrons.

“Current collector” refers to a part of an electrical energy storageand/or distribution device which provides an electrical connection tofacilitate the flow of electricity in to, or out of, the device. Currentcollectors often comprise metal and/or other conductive materials andmay be used as a backing for electrodes to facilitate the flow ofelectricity to and from the electrode.

“Electrolyte” means a substance containing free ions such that thesubstance is electrically conductive. Electrolytes are commonly employedin electrical energy storage devices. Examples of electrolytes include,but are not limited to, solvents such as propylene carbonate, ethylenecarbonate, butylene carbonate, dimethyl carbonate, methyl ethylcarbonate, diethyl carbonate, sulfolane, methylsulfolane, acetonitrileor mixtures thereof in combination with solutes such astetralkylammonium salts such as TEA TFB (tetraethylammoniumtetrafluoroborate), MTEATFB (methyltriethylammonium tetrafluoroborate),EMITFB (1-ethyl-3-methylimidazolium tetrafluoroborate),tetraethylammonium, triethylammonium based salts or mixtures thereof. Insome embodiments, the electrolyte can be a water-based acid orwater-based base electrolyte such as mild aqueous sulfuric acid oraqueous potassium hydroxide.

A. Carbon Materials Comprising Optimized Pore Size Distributions

As noted above, one embodiment of the present disclosure is a carbonmaterial comprising an optimized pore size distribution. The optimizedpore size distribution contributes to the superior performance ofelectrical devices comprising the carbon materials relative to devicescomprising other known carbon materials. For example, in someembodiments, the carbon material comprises an optimized blend of bothmicropores and mesopores and may also comprise low surface functionalityupon pryolysis and/or activation. In other embodiments, the carbonmaterial comprises a total of less than 500 ppm of all elements havingatomic numbers ranging from 11 to 92, as measured by proton inducedx-ray emission. The high purity and optimized micropore/mesoporedistribution make the carbon materials ideal for use in electricalstorage and distribution devices, for example ultracapacitors.

The optimized pore size distributions, as well as the high purity, ofthe disclosed carbon materials can be attributed to the disclosed solgel methods and subsequent post-polymerization processing of the polymergels (e.g., pyrolysis and/or activation). Applicants have discoveredthat when one or more polymer precursors, for example a phenoliccompound and an aldehyde, are co-polymerized under acidic conditions inthe presence of a volatile basic catalyst, an ultrapure polymer gelresults. This is in contrast to other reported methods for thepreparation of polymer gels which result in polymer gels comprisingresidual levels of undesired impurities. Pyrolysis and/or activation ofthe ultrapure polymer gels under the disclosed conditions results in anultrapure carbon material having an optimized pore size distribution.

The properties of the disclosed carbon materials, as well as methods fortheir preparation are discussed in more detail below.

1. Polymer Gels

Polymer gels are intermediates in the preparation of the disclosedcarbon materials. As such, the physical and chemical properties of thepolymer gels contribute to the properties of the carbon materials.

In other embodiments, the polymer gel comprises a total of less than 500ppm of all other elements (i.e., excluding the electrochemical modifier)having atomic numbers ranging from 11 to 92. For example, in some otherembodiments the polymer gel comprises less than 200 ppm, less than 100ppm, less than 50 ppm, less than 25 ppm, less than 10 ppm, less than 5ppm or less than 1 ppm of all other elements having atomic numbersranging from 11 to 92. In some embodiments, the electrochemical modifiercontent and impurity content of the polymer gels can be determined byproton induced x-ray emission (PUCE) analysis.

In some embodiments, the polymer gel is a dried polymer gel, forexample, a polymer cryogel. In other embodiments, the dried polymer gelis a polymer xerogel or a polymer aerogel. In some embodiments, thepolymer gels are prepared from phenolic compounds and aldehydecompounds, for example, in one embodiment, the polymer gels can beproduced from resorcinol and formaldehyde. In other embodiments, thepolymer gels are produced under acidic conditions, and in otherembodiments the polymer gels are produced in the presence of theelectrochemical modifier. In some embodiments, acidity can be providedby dissolution of a solid acid compound, by employing an acid as thereaction solvent or by employing a mixed solvent system where one of thesolvents is an acid. Preparation of the polymer gels is described inmore detail below.

The disclosed process comprises polymerization to form a polymer gel inthe presence of a basic volatile catalyst. Accordingly, in someembodiments, the polymer gel comprises one or more salts, for example,in some embodiments the one or more salts are basic volatile salts.Examples of basic volatile salts include, but are not limited to,ammonium carbonate, ammonium bicarbonate, ammonium acetate, ammoniumhydroxide, and combinations thereof. Accordingly, in some embodiments,the present disclosure provides a polymer gel comprising ammoniumcarbonate, ammonium bicarbonate, ammonium acetate, ammonium hydroxide,or combinations thereof. In further embodiments, the polymer gelcomprises ammonium carbonate. In other further embodiments, the polymergel comprises ammonium acetate.

The polymer gels may also comprise low ash content which may contributeto the low ash content of a carbon material prepared therefrom. Thus, insome embodiments, the ash content of the polymer gel ranges from 0.1% to0.001%. In other embodiments, the ash content of the polymer gel is lessthan 0.1%, less than 0.08%, less than 0.05%, less than 0.03%, less than0.025%, less than 0.01%, less than 0.0075%, less than 0.005% or lessthan 0.001%.

In other embodiments, the polymer gel has a total PIXE impurity contentof all other elements of less than 500 ppm and an ash content of lessthan 0.08%. In a further embodiment, the polymer gel has a total PIXEimpurity content of all other elements of less than 300 ppm and an ashcontent of less than 0.05%. In another further embodiment, the polymergel has a total PIXE impurity content of all other elements of less than200 ppm and an ash content of less than 0.02%. In another furtherembodiment, the polymer gel has a total PIXE impurity content of allother elements of less than 200 ppm and an ash content of less than0.01%.

As noted above, polymer gels comprising impurities generally yieldcarbon materials which also comprise impurities. Accordingly, one aspectof the present disclosure is a polymer gel with low levels of residualundesired impurities. The amount of individual PIXE impurities presentin the polymer gel can be determined by proton induced x-ray emission.In some embodiments, the level of sodium present in the polymer gel isless than 1000 ppm, less than 500 ppm, less than 100 ppm, less than 50ppm, less than 10 ppm, or less than 1 ppm. In some embodiments, thelevel of magnesium present in the polymer gel is less than 1000 ppm,less than 100 ppm, less than 50 ppm, less than 10 ppm, or less than 1ppm. As noted above, in some embodiments other impurities such ashydrogen, oxygen and/or nitrogen may be present in levels ranging fromless than 10% to less than 0.01%.

In some specific embodiments, the polymer gel comprises less than 100ppm sodium, less than 300 ppm silicon, less than 50 ppm sulfur, lessthan 100 ppm calcium, less than 20 ppm iron, less than 10 ppm nickel,less than 40 ppm copper, less than 5 ppm chromium and less than 5 ppmzinc. In other specific embodiments, the polymer gel comprises less than50 ppm sodium, less than 100 ppm silicon, less than 30 ppm sulfur, lessthan 50 ppm calcium, less than 10 ppm iron, less than 5 ppm nickel, lessthan 20 ppm copper, less than 2 ppm chromium and less than 2 ppm zinc.

In other specific embodiments, the polymer gel comprises less than 50ppm sodium, less than 50 ppm silicon, less than 30 ppm sulfur, less than10 ppm calcium, less than 2 ppm iron, less than 1 ppm nickel, less than1 ppm copper, less than 1 ppm chromium and less than 1 ppm zinc.

In some other specific embodiments, the polymer gel comprises less than100 ppm sodium, less than 50 ppm magnesium, less than 50 ppm aluminum,less than 10 ppm sulfur, less than 10 ppm chlorine, less than 10 ppmpotassium, less than 1 ppm chromium and less than 1 ppm manganese.

The disclosed method yields a polymer gel comprising a high specificsurface area. Without being bound by theory, it is believed that thesurface area of the polymer gel contributes, at least in part, to thedesirable surface area properties of the carbon materials. The surfacearea can be measured using the BET technique well-known to those ofskill in the art. In one embodiment of any of the aspects disclosedherein the polymer gel comprises a BET specific surface area of at least150 m²/g, at least 250 m²/g, at least 400 m²/g, at least 500 m²/g, atleast 600 m²/g or at least 700 m²/g.

In one embodiment, the polymer gel comprises a BET specific surface areaof 100 m²/g to 1000 m²/g. Alternatively, the polymer gel comprises a BETspecific surface area of between 150 m²/g and 900 m²/g. Alternatively,the polymer gel comprises a BET specific surface area of between 400m²/g and 800 m²/g.

In one embodiment, the polymer gel comprises a tap density of from 0.10g/cc to 0.60 g/cc. In one embodiment, the polymer gel comprises a tapdensity of from 0.15 g/cc to 0.25 g/cc. In one embodiment of the presentdisclosure, the polymer gel comprises a BET specific surface area of atleast 150 m²/g and a tap density of less than 0.60 g/cc. Alternately,the polymer gel comprises a BET specific surface area of at least 250m²/g and a tap density of less than 0.4 g/cc. In another embodiment, thepolymer gel comprises a BET specific surface area of at least 500 m²/gand a tap density of less than 0.30 g/cc.

In another embodiment of any of the aspects or variations disclosedherein the polymer gel comprises a residual water content of less than15%, less than 13%, less than 10%, less than 5% or less than 1%.

In one embodiment, the polymer gel comprises a fractional pore volume ofpores at or below 500 angstroms that comprises at least 25% of the totalpore volume, 50% of the total pore volume, at least 75% of the totalpore volume, at least 90% of the total pore volume or at least 99% ofthe total pore volume. In another embodiment, the polymer gel comprisesa fractional pore volume of pores at or below 20 nm that comprises atleast 50% of the total pore volume, at least 75% of the total porevolume, at least 90% of the total pore volume or at least 99% of thetotal pore volume.

In some embodiments, the amount of nitrogen adsorbed per mass of polymergel at 0.11 relative pressure is at least 10% of the total nitrogenadsorbed up to 0.99 relative pressure or at least 20% of the totalnitrogen adsorbed up to 0.99 relative pressure. In another embodiment,the amount of nitrogen adsorbed per mass of polymer gel at 0.11 relativepressure is between 10% and 50% of the total nitrogen adsorbed up to0.99 relative pressure, is between 20% and 40% of the total nitrogenadsorbed up to 0.99 relative pressure or is between 20% and 30% of thetotal nitrogen adsorbed up to 0.99 relative pressure.

In one embodiment, the polymer gel comprises a fractional pore surfacearea of pores at or below 100 nm that comprises at least 50% of thetotal pore surface area, at least 75% of the total pore surface area, atleast 90% of the total pore surface area or at least 99% of the totalpore surface area. In another embodiment, the polymer gel comprises afractional pore surface area of pores at or below 20 nm that comprisesat least 50% of the total pore surface area, at least 75% of the totalpore surface area, at least 90% of the total pore surface or at least99% of the total pore surface area.

As described in more detail below, methods for preparing the disclosedcarbon materials may include pyrolysis of a polymer gel. In someembodiments, the pyrolyzed polymer gels have a surface area from about100 to about 1200 m²/g. In other embodiments, the pyrolyzed polymer gelshave a surface area from about 500 to about 800 m²/g. In otherembodiments, the pyrolyzed polymer gels have a surface area from about500 to about 700 m²/g.

In other embodiments, the pyrolyzed polymer gels have a tap density fromabout 0.1 to about 1.0 g/cc. In other embodiments, the pyrolyzed polymergels have a tap density from about 0.3 to about 0.6 g/cc. In otherembodiments, the pyrolyzed polymer gels have a tap density from about0.3 to about 0.5 g/cc.

The polymer gels can be prepared by the polymerization of one or morepolymer precursors in an appropriate solvent system under catalyticconditions. The electrochemical modifier can be incorporated into thegel either during or after the polymerization process. Accordingly, inone embodiment the polymer gel is prepared by admixing one or moremiscible solvents, one or more phenolic compounds, one or morealdehydes, one or more catalysts and an electrochemical modifier. Forexample in a further embodiment the polymer gel is prepared by admixingwater, acetic acid, resorcinol, formaldehyde, ammonium acetate and leadacetate. Preparation of polymers gels, and carbon materials, from thesame is discussed in more detail below.

2. Carbon Materials

The present disclosure is directed to a carbon material comprising anoptimized pore structure. While not wishing to be bound by theory, it isbelieved that, in addition to the pore structure, the purity profile,surface area and other properties of the carbon materials are a functionof its preparation method, and variation of the preparation parametersmay yield carbon materials having different properties. Accordingly, insome embodiments, the carbon material is a pyrolyzed dried polymer gel,for example, a pyrolyzed polymer cryogel, a pyrolyzed polymer xerogel ora pyrolyzed polymer aerogel. In other embodiments, the carbon materialis pyrolyzed and activated (e.g., a synthetic activated carbonmaterial). For example, in further embodiments the carbon material is anactivated dried polymer gel, an activated polymer cryogel, an activatedpolymer xerogel or an activated polymer aerogel.

As noted above, activated carbon particles are widely employed as anenergy storage material. In this regard, a critically importantcharacteristic is high power density, which is possible with electrodesthat have low ionic resistance that yield high frequency response. It isimportant to achieve a low ionic resistance, for instance in situationswith device ability to respond to cyclic performance is a constraint.The disclosed carbon material solves the problem of how to optimize anelectrode formulation and maximize the power performance of electricalenergy storage and distribution devices. Devices comprising the carbonmaterials exhibit long-term stability, fast response time and high pulsepower performance.

The disclosed methods produce carbon materials comprising specificmicropore structure, which is typically described in terms of fraction(percent) of total pore volume residing in either micropores ormesopores or both. Accordingly, in some embodiments the pore structureof the carbon materials comprises from 10% to 90% micropores. In someother embodiments the pore structure of the carbon materials comprisesfrom 20% to 80% micropores. In other embodiments, the pore structure ofthe carbon materials comprises from 30% to 70% micropores. In otherembodiments, the pore structure of the carbon materials comprises from40% to 60% micropores. In other embodiments, the pore structure of thecarbon materials comprises from 40% to 50% micropores. In otherembodiments, the pore structure of the carbon materials comprises from43% to 47% micropores. In certain embodiments, the pore structure of thecarbon materials comprises about 45% micropores.

In some other embodiments the pore structure of the carbon materialscomprises from 20% to 50% micropores. In still other embodiments thepore structure of the carbon materials comprises from 20% to 40%micropores, for example from 25% to 35% micropores or 27% to 33%micropores. In some other embodiments, the pore structure of the carbonmaterials comprises from 30% to 50% micropores, for example from 35% to45% micropores or 37% to 43% micropores. In some certain embodiments,the pore structure of the carbon materials comprises about 30%micropores or about 40% micropores.

In some other embodiments the pore structure of the carbon materialscomprises from 40% to 90% micropores. In still other embodiments thepore structure of the carbon materials comprises from 45% to 90%micropores, for example from 55% to 85% micropores. In some otherembodiments, the pore structure of the carbon materials comprises from65% to 85% micropores, for example from 75% to 85% micropores or 77% to83% micropores. In yet other embodiments the pore structure of thecarbon materials comprises from 65% to 75% micropores, for example from67% to 73% micropores. In some certain embodiments, the pore structureof the carbon materials comprises about 80% micropores or about 70%micropores.

The mesoporosity of the carbon materials contributes to high ionmobility and low resistance. In some embodiments, the pore structure ofthe carbon materials comprises from 10% to 90% mesopores. In some otherembodiments, the pore structure of the carbon materials comprises from20% to 80% mesopores. In other embodiments, the pore structure of thecarbon materials comprises from 30% to 70% mesopores. In otherembodiments, the pore structure of the carbon materials comprises from40% to 60% mesopores. In other embodiments, the pore structure of thecarbon materials comprises from 50% to 60% mesopores. In otherembodiments, the pore structure of the carbon materials comprises from53% to 57% mesopores. In other embodiments, the pore structure of thecarbon materials comprises about 55% mesopores.

In some other embodiments the pore structure of the carbon materialscomprises from 50% to 80% mesopores. In still other embodiments the porestructure of the carbon materials comprises from 60% to 80% mesopores,for example from 65% to 75% mesopores or 67% to 73% mesopores. In someother embodiments, the pore structure of the carbon materials comprisesfrom 50% to 70% mesopores, for example from 55% to 65% mesopores or 57%to 53% mesopores. In some certain embodiments, the pore structure of thecarbon materials comprises about 30% mesopores or about 40% mesopores.

In some other embodiments the pore structure of the carbon materialscomprises from 10% to 60% mesopores. In some other embodiments the porestructure of the carbon materials comprises from 10% to 55% mesopores,for example from 15% to 45% mesopores or from 15% to 40% mesopores. Insome other embodiments, the pore structure of the carbon materialscomprises from 15% to 35% mesopores, for example from 15% to 25%mesopores or from 17% to 23% mesopores. In some other embodiments, thepore structure of the carbon materials comprises from 25% to 35%mesopores, for example from 27% to 33% mesopores. In some certainembodiments, the pore structure of the carbon materials comprises about20% mesopores and in other embodiments the carbon materials compriseabout 30% mesopores.

The optimized blend of micropores and mesopores within the carbonmaterials contributes to the enhanced electrochemical performance of thesame. Thus, in some embodiments the pore structure of the carbonmaterials comprises from 10% to 90% micropores and from 10% to 90%mesopores. In some other embodiments the pore structure of the carbonmaterials comprises from 20% to 80% micropores and from 20% to 80%mesopores. In other embodiments, the pore structure of the carbonmaterials comprises from 30% to 70% micropores and from 30% to 70%mesopores. In other embodiments, the pore structure of the carbonmaterials comprises from 40% to 60% micropores and from 40% to 60%mesopores. In other embodiments, the pore structure of the carbonmaterials comprises from 40% to 50% micropores and from 50% to 60%mesopores. In other embodiments, the pore structure of the carbonmaterials comprises from 43% to 47% micropores and from 53% to 57%mesopores. In other embodiments, the pore structure of the carbonmaterials comprises about 45% micropores and about 55% mesopores.

In still other embodiments, the pore structure of the carbon materialscomprises from 40% to 90% micropores and from 10% to 60% mesopores. Inother embodiments, the pore structure of the carbon materials comprisesfrom 45% to 90% micropores and from 10% to 55% mesopores. In otherembodiments, the pore structure of the carbon materials comprises from40% to 85% micropores and from 15% to 40% mesopores. In yet otherembodiments, the pore structure of the carbon materials comprises from55% to 85% micropores and from 15% to 45% mesopores, for example from65% to 85% micropores and from 15% to 35% mesopores. In otherembodiments, the pore structure of the carbon materials comprises from65% to 75% micropores and from 15% to 25% mesopores, for example from67% to 73% micropores and from 27% to 33% mesopores In some otherembodiments, the pore structure of the carbon materials comprises from75% to 85% micropores and from 15% to 25% mesopores, for example from83% to 77% micropores and from 17% to 23% mesopores. In other certainembodiments, the pore structure of the carbon materials comprises about80% micropores and about 20% mesopores, or in other embodiments, thepore structure of the carbon materials comprises about 70% microporesand about 30% mesopores.

In still other embodiments, the pore structure comprises from 20% to 50%micropores, and from 50% to 80% mesopores. For example, in someembodiments, from 20% to 40% of the total pore volume resides inmicropores and from 60% to 80% of the total pore volume resides inmesopores. In other embodiments, from 25% to 35% of the total porevolume resides in micropores and from 65% to 75% of the total porevolume resides in mesopores. For example, in some embodiments about 30%of the total pore volume resides in micropores and about 70% of thetotal pore volume resides in mesopores.

In still other embodiments, from 30% to 50% of the total pore volumeresides in micropores and from 50% to 70% of the total pore volumeresides in mesopores. In other embodiments, from 35% to 45% of the totalpore volume resides in micropores and from 55% to 65% of the total porevolume resides in mesopores. For example, in some embodiments, about 40%of the total pore volume resides in micropores and about 60% of thetotal pore volume resides in mesopores.

In other variations of any of the foregoing carbon materials, the carbonmaterials do not have a substantial volume of pores greater than 20 nm.For example, in certain embodiments the carbon materials comprise lessthan 50%, less than 40%, less than 30%, less than 25%, less than 20%,less than 15%, less than 10%, less than 5%, less than 2.5% or even lessthan 1% of the total pore volume in pores greater than 20 nm.

The porosity of the carbon materials contributes to their enhancedelectrochemical performance. Accordingly, in one embodiment the carbonmaterial comprises a pore volume residing in pores less than 20angstroms of at least 1.8 cc/g, at least 1.2, at least 0.6, at least0.30 cc/g, at least 0.25 cc/g, at least 0.20 cc/g or at least 0.15 cc/g.In other embodiments, the carbon material comprises a pore volumeresiding in pores greater than 20 angstroms of at least 4.00 cc/g, atleast 3.75 cc/g, at least 3.50 cc/g, at least 3.25 cc/g, at least 3.00cc/g, at least 2.75 cc/g, at least 2.50 cc/g, at least 2.25 cc/g, atleast 2.00 cc/g, at least 1.90 cc/g, 1.80 cc/g, 1.70 cc/g, 1.60 cc/g,1.50 cc/g, 1.40 cc/g, at least 1.30 cc/g, at least 1.20 cc/g, at least1.10 cc/g, at least 1.00 cc/g, at least 0.85 cc/g, at least 0.80 cc/g,at least 0.75 cc/g, at least 0.70 cc/g, at least 0.65 cc/g, or at least0.5 cc/g.

In other embodiments, the carbon material comprises a pore volume of atleast 4.00 cc/g, at least 3.75 cc/g, at least 3.50 cc/g, at least 3.25cc/g, at least 3.00 cc/g, at least 2.75 cc/g, at least 2.50 cc/g, atleast 2.25 cc/g, at least 2.00 cc/g, at least 1.90 cc/g, 1.80 cc/g, 1.70cc/g, 1.60 cc/g, 1.50 cc/g, 1.40 cc/g, at least 1.30 cc/g, at least 1.20cc/g, at least 1.10 cc/g, at least 1.00 cc/g, at least 0.85 cc/g, atleast 0.80 cc/g, at least 0.75 cc/g, at least 0.70 cc/g, at least 0.65cc/g or at least 0.50 cc/g for pores ranging from 20 angstroms to 300angstroms.

In yet other embodiments, the carbon materials comprise a total porevolume of at least 4.00 cc/g, at least 3.75 cc/g, at least 3.50 cc/g, atleast 3.25 cc/g, at least 3.00 cc/g, at least 2.75 cc/g, at least 2.50cc/g, at least 2.25 cc/g, at least 2.00 cc/g, at least 1.90 cc/g, 1.80cc/g, 1.70 cc/g, 1.60 cc/g, 1.50 cc/g, 1.40 cc/g, at least 1.30 cc/g, atleast 1.20 cc/g, at least 1.10 cc/g, at least 1.00 cc/g, at least 0.85cc/g, at least 0.80 cc/g, at least 0.75 cc/g, at least 0.70 cc/g, atleast 0.65 cc/g, at least 0.60 cc/g, at least 0.55 cc/g, at least 0.50cc/g, at least 0.45 cc/g, at least 0.40 cc/g, at least 0.35 cc/g, atleast 0.30 cc/g, at least 0.25 cc/g or at least 0.20 cc/g.

In yet other embodiments, the carbon materials comprise a pore volumeresiding in pores of less than 20 angstroms of at least 0.2 cc/g and apore volume residing in pores of between 20 and 300 angstroms of atleast 0.8 cc/g. In yet other embodiments, the carbon materials comprisea pore volume residing in pores of less than 20 angstroms of at least0.5 cc/g and a pore volume residing in pores of between 20 and 300angstroms of at least 0.5 cc/g. In yet other embodiments, the carbonmaterials comprise a pore volume residing in pores of less than 20angstroms of at least 0.6 cc/g and a pore volume residing in pores ofbetween 20 and 300 angstroms of at least 2.4 cc/g. In yet otherembodiments, the carbon materials comprise a pore volume residing inpores of less than 20 angstroms of at least 1.5 cc/g and a pore volumeresiding in pores of between 20 and 300 angstroms of at least 1.5 cc/g.

In certain embodiments a mesoporous carbon material having low porevolume in the micropore region (e.g., less than 60%, less than 50%, lessthan 40%, less than 30%, less than 20% microporosity) is provided. Forexample, the mesoporous carbon can be a polymer gel that has beenpyrolyzed, but not activated. In some embodiments, the pyrolyzedmesoporous carbon comprises a specific surface area of at least 400m²/g, at least 500 m²/g, at least 600 m²/g, at least 675 m²/g or atleast 750 m²/g. In other embodiments, the mesoporous carbon materialcomprises a total pore volume of at least 0.50 cc/g, at least 0.60 cc/g,at least 0.70 cc/g, at least 0.80 cc/g or at least 0.90 cc/g. In yetother embodiments, the mesoporous carbon material comprises a tapdensity of at least 0.30 g/cc, at least 0.35 g/cc, at least 0.40 g/cc,at least 0.45 g/cc, at least 0.50 g/cc or at least 0.55 g/cc.

The carbon material comprises low total PIXE impurities (excluding theelectrochemical modifier). Thus, in some embodiments the total PIXEimpurity content (excluding the electrochemical modifier) of all otherPIXE elements in the carbon material (as measured by proton inducedx-ray emission) is less than 1000 ppm. In other embodiments, the totalPIXE impurity content (excluding the electrochemical modifier) of allother PIXE elements in the carbon material is less than 800 ppm, lessthan 500 ppm, less than 300 ppm, less than 200 ppm, less than 150 ppm,less than 100 ppm, less than 50 ppm, less than 25 ppm, less than 10 ppm,less than 5 ppm or less than 1 ppm. In further embodiments of theforegoing, the carbon material is a pyrolyzed dried polymer gel, apyrolyzed polymer cryogel, a pyrolyzed polymer xerogel, a pyrolyzedpolymer aerogel, an activated dried polymer gel, an activated polymercryogel, an activated polymer xerogel or an activated polymer aerogel.

In addition to low content of undesired PIXE impurities, the disclosedcarbon materials may comprise high total carbon content. In addition tocarbon, the carbon material may also comprise oxygen, hydrogen, nitrogenand the electrochemical modifier. In some embodiments, the materialcomprises at least 75% carbon, 80% carbon, 85% carbon, at least 90%carbon, at least 95% carbon, at least 96% carbon, at least 97% carbon,at least 98% carbon or at least 99% carbon on a weight/weight basis. Insome other embodiments, the carbon material comprises less than 10%oxygen, less than 5% oxygen, less than 3.0% oxygen, less than 2.5%oxygen, less than 1% oxygen or less than 0.5% oxygen on a weight/weightbasis. In other embodiments, the carbon material comprises less than 10%hydrogen, less than 5% hydrogen, less than 2.5% hydrogen, less than 1%hydrogen, less than 0.5% hydrogen or less than 0.1% hydrogen on aweight/weight basis. In other embodiments, the carbon material comprisesless than 5% nitrogen, less than 2.5% nitrogen, less than 1% nitrogen,less than 0.5% nitrogen, less than 0.25% nitrogen or less than 0.01%nitrogen on a weight/weight basis. The oxygen, hydrogen and nitrogencontent of the disclosed carbon materials can be determined bycombustion analysis. Techniques for determining elemental composition bycombustion analysis are well known in the art.

The total ash content of the carbon material may, in some instances,have an effect on the electrochemical performance of the carbonmaterial. Accordingly, in some embodiments, the ash content of thecarbon material ranges from 0.1% to 0.001% weight percent ash, forexample in some specific embodiments the ash content of the carbonmaterial is less than 0.1%, less than 0.08%, less than 0.05%, less than0.03%, than 0.025%, less than 0.01%, less than 0.0075%, less than 0.005%or less than 0.001%.

In other embodiments, the carbon material comprises a total PIXEimpurity content of less than 500 ppm and an ash content of less than0.08%. In further embodiments, the carbon material comprises a totalPIXE impurity content of less than 300 ppm and an ash content of lessthan 0.05%. In other further embodiments, the carbon material comprisesa total PIXE impurity content of less than 200 ppm and an ash content ofless than 0.05%. In other further embodiments, the carbon materialcomprises a total PIXE impurity content of less than 200 ppm and an ashcontent of less than 0.025%. In other further embodiments, the carbonmaterial comprises a total PIXE impurity content of less than 100 ppmand an ash content of less than 0.02%. In other further embodiments, thecarbon material comprises a total PIXE impurity content of less than 50ppm and an ash content of less than 0.01%.

The amount of individual PIXE impurities present in the disclosed carbonmaterials can be determined by proton induced x-ray emission. IndividualPIXE impurities may contribute in different ways to the overallelectrochemical performance of the disclosed carbon materials. Thus, insome embodiments, the level of sodium present in the carbon material isless than 1000 ppm, less than 500 ppm, less than 100 ppm, less than 50ppm, less than 10 ppm, or less than 1 ppm. As noted above, in someembodiments other impurities such as hydrogen, oxygen and/or nitrogenmay be present in levels ranging from less than 10% to less than 0.01%.

In some embodiments, the carbon material comprises undesired PIXEimpurities near or below the detection limit of the proton induced x-rayemission analysis. For example, in some embodiments the carbon materialcomprises less than 50 ppm sodium, less than 15 ppm magnesium, less than10 ppm aluminum, less than 8 ppm silicon, less than 4 ppm phosphorous,less than 3 ppm sulfur, less than 3 ppm chlorine, less than 2 ppmpotassium, less than 3 ppm calcium, less than 2 ppm scandium, less than1 ppm titanium, less than 1 ppm vanadium, less than 0.5 ppm chromium,less than 0.5 ppm manganese, less than 0.5 ppm iron, less than 0.25 ppmcobalt, less than 0.25 ppm nickel, less than 0.25 ppm copper, less than0.5 ppm zinc, less than 0.5 ppm gallium, less than 0.5 ppm germanium,less than 0.5 ppm arsenic, less than 0.5 ppm selenium, less than 1 ppmbromine, less than 1 ppm rubidium, less than 1.5 ppm strontium, lessthan 2 ppm yttrium, less than 3 ppm zirconium, less than 2 ppm niobium,less than 4 ppm molybdenum, less than 4 ppm, technetium, less than 7 ppmrubidium, less than 6 ppm rhodium, less than 6 ppm palladium, less than9 ppm silver, less than 6 ppm cadmium, less than 6 ppm indium, less than5 ppm tin, less than 6 ppm antimony, less than 6 ppm tellurium, lessthan 5 ppm iodine, less than 4 ppm cesium, less than 4 ppm barium, lessthan 3 ppm lanthanum, less than 3 ppm cerium, less than 2 ppmpraseodymium, less than 2 ppm, neodymium, less than 1.5 ppm promethium,less than 1 ppm samarium, less than 1 ppm europium, less than 1 ppmgadolinium, less than 1 ppm terbium, less than 1 ppm dysprosium, lessthan 1 ppm holmium, less than 1 ppm erbium, less than 1 ppm thulium,less than 1 ppm ytterbium, less than 1 ppm lutetium, less than 1 ppmhafnium, less than 1 ppm tantalum, less than 1 ppm tungsten, less than1.5 ppm rhenium, less than 1 ppm osmium, less than 1 ppm iridium, lessthan 1 ppm platinum, less than 1 ppm silver, less than 1 ppm mercury,less than 1 ppm thallium, less than 1 ppm lead, less than 1.5 ppmbismuth, less than 2 ppm thorium, or less than 4 ppm uranium.

In some specific embodiments, the carbon material comprises less than100 ppm sodium, less than 300 ppm silicon, less than 50 ppm sulfur, lessthan 100 ppm calcium, less than 20 ppm iron, less than 10 ppm nickel,less than 140 ppm copper, less than 5 ppm chromium and less than 5 ppmzinc as measured by proton induced x-ray emission. In other specificembodiments, the carbon material comprises less than 50 ppm sodium, lessthan 30 ppm sulfur, less than 100 ppm silicon, less than 50 ppm calcium,less than 10 ppm iron, less than 5 ppm nickel, less than 20 ppm copper,less than 2 ppm chromium and less than 2 ppm zinc.

In other specific embodiments, the carbon material comprises less than50 ppm sodium, less than 50 ppm silicon, less than 30 ppm sulfur, lessthan 10 ppm calcium, less than 2 ppm iron, less than 1 ppm nickel, lessthan 1 ppm copper, less than 1 ppm chromium and less than 1 ppm zinc.

In some other specific embodiments, the carbon material comprises lessthan 100 ppm sodium, less than 50 ppm magnesium, less than 50 ppmaluminum, less than 10 ppm sulfur, less than 10 ppm chlorine, less than10 ppm potassium, less than 1 ppm chromium and less than 1 ppmmanganese.

In some embodiments, the carbon materials comprise less than 10 ppmiron. In other embodiments, the carbon materials comprise less than 3ppm nickel. In other embodiments, the carbon materials comprise lessthan 30 ppm sulfur. In other embodiments, the carbon materials compriseless than 1 ppm chromium. In other embodiments, the carbon materialscomprise less than 1 ppm copper. In other embodiments, the carbonmaterials comprise less than 1 ppm zinc.

The disclosed carbon materials also comprise a high surface area. Whilenot wishing to be bound by theory, it is thought that such high surfacearea may contribute, at least in part, to their superior electrochemicalperformance. Accordingly, in some embodiments, the carbon materialcomprises a BET specific surface area of at least 100 m²/g, at least 300m²/g, at least 500 m²/g, at least 1000 m²/g, at least 1500 m²/g, atleast 2000 m²/g, at least 2400 m²/g, at least 2500 m²/g, at least 2750m²/g or at least 3000 m²/g. In other embodiments, the BET specificsurface area ranges from about 100 m²/g to about 3000 m²/g, for examplefrom about 500 m²/g to about 1000 m²/g, from about 1000 m²/g to about1500 m²/g, from about 1500 m²/g to about 2000 m²/g, from about 2000 m²/gto about 2500 m²/g or from about 2500 m²/g to about 3000 m²/g. Forexample, in some embodiments of the foregoing, the carbon material isactivated.

In still other examples, the carbon material comprises less than 100 ppmsodium, less than 100 ppm silicon, less than 10 ppm sulfur, less than 25ppm calcium, less than 1 ppm iron, less than 2 ppm nickel, less than 1ppm copper, less than 1 ppm chromium, less than 50 ppm magnesium, lessthan 10 ppm aluminum, less than 25 ppm phosphorous, less than 5 ppmchlorine, less than 25 ppm potassium, less than 2 ppm titanium, lessthan 2 ppm manganese, less than 0.5 ppm cobalt and less than 5 ppm zincas measured by proton induced x-ray emission, and wherein all otherelements having atomic numbers ranging from 11 to 92 are undetected byproton induced x-ray emission.

In another embodiment, the carbon material comprises a tap densitybetween 0.1 and 1.0 g/cc, between 0.2 and 0.8 g/cc, between 0.3 and 0.5g/cc or between 0.4 and 0.5 g/cc. In another embodiment, the carbonmaterial has a total pore volume of at least 0.1 cm³/g, at least 0.2cm³/g, at least 0.3 cm³/g, at least 0.4 cm3/g, at least 0.5 cm³/g, atleast 0.7 cm³/g, at least 0.75 cm³/g, at least 0.9 cm³/g, at least 1.0cm³/g, at least 1.1 cm³/g, at least 1.2 cm³/g, at least 1.3 cm³/g, atleast 1.4 cm³/g, at least 1.5 cm³/g or at least 1.6 cm³/g.

The pore size distribution of the disclosed carbon materials is oneparameter that may have an effect on the electrochemical performance ofthe carbon materials. For example, the carbon materials may comprisemesopores with a short effective length (i.e., less than 10 nm, lessthan 5, nm or less than 3 nm as measured by TEM) which decreases iondiffusion distance and may be useful to enhance ion transport andmaximize power.

In another embodiment, the carbon material comprises a fractional poresurface area of pores between 20 and 300 angstroms that comprises atleast 40% of the total pore surface area, at least 50% of the total poresurface area, at least 70% of the total pore surface area or at least80% of the total pore surface area. In another embodiment, the carbonmaterial comprises a fractional pore surface area of pores at or below20 nm that comprises at least 20% of the total pore surface area, atleast 30% of the total pore surface area, at least 40% of the total poresurface area or at least 50% of the total pore surface area.

In another embodiment, the carbon material comprises pores predominantlyin the range of 1000 angstroms or lower, for example 100 angstroms orlower, for example 50 angstroms or lower. Alternatively, the carbonmaterial comprises micropores in the range of 0-20 angstroms andmesopores in the range of 20-300 angstroms. The ratio of pore volume orpore surface in the micropore range compared to the mesopore range canbe in the range of 95:5 to 5:95. Alternatively, the ratio of pore volumeor pore surface in the micropore range compared to the mesopore rangecan be in the range of 20:80 to 60:40.

In other embodiments, the carbon materials are mesoporous and comprisemonodisperse mesopores. As used herein, the term “monodisperse” whenused in reference to a pore size refers generally to a span (furtherdefined as (Dv90-Dv10)/Dv, 50 where Dv10, Dv50 and Dv90 refer to thepore size at 10%, 50% and 90% of the distribution by volume of about 3or less, typically about 2 or less, often about 1.5 or less.

Yet in other embodiments, the carbons materials comprise a pore volumeof at least 1 cc/g, at least 2 cc/g, at least 3 cc/g, at least 4 cc/g orat least 7 cc/g. In one particular embodiment, the carbon materialscomprise a pore volume of from 1 cc/g to 7 cc/g.

In other embodiments, the carbon materials comprise at least 50% of thetotal pore volume residing in pores with a diameter ranging from 50 Å to5000 Å. In some instances, the carbon materials comprise at least 50% ofthe total pore volume residing in pores with a diameter ranging from 50Å to 500 Å. Still in other instances, the carbon materials comprise atleast 50% of the total pore volume residing in pores with a diameterranging from 500 Å to 1000 Å. Yet in other instances, the carbonmaterials comprise at least 50% of the total pore volume residing inpores with a diameter ranging from 1000 Å to 5000 Å.

In some embodiments, the mean particle diameter for the carbon materialsranges from 1 to 1000 microns. In other embodiments the mean particlediameter for the carbon materials ranges from 1 to 100 microns. Still inother embodiments the mean particle diameter for the carbon materialsranges from 1 to 50 microns. Yet in other embodiments, the mean particlediameter for the carbon materials ranges from 5 to 15 microns or from 1to 5 microns. Still in other embodiments, the mean particle diameter forthe carbon materials is about 10 microns. Still in other embodiments,the mean particle diameter for the carbon materials is less than 4, isless than 3, is less than 2, is less than 1 microns.

In some embodiments, the carbon materials exhibit a mean particlediameter ranging from 1 nm to 10 nm. In other embodiments, the meanparticle diameter ranges from 10 nm to 20 nm. Yet in other embodiments,the mean particle diameter ranges from 20 nm to 30 nm. Still in otherembodiments, the mean particle diameter ranges from 30 nm to 40 nm. Yetstill in other embodiments, the mean particle diameter ranges from 40 nmto 50 nm. In other embodiments, the mean particle diameter ranges from50 nm to 100 nm.

In another embodiment of the present disclosure, the carbon material isprepared by a method disclosed herein, for example, in some embodimentsthe carbon material is prepared by a method comprising pyrolyzing adried polymer gel as disclosed herein. In some embodiments, thepyrolyzed polymer gel is further activated to obtain an activated carbonmaterial. Carbon materials comprising an electrochemical modifier can beprepared by any number of methods described in more detail below.

B. Preparation of Carbon Materials Comprising Optimized Pore SizeDistributions

Methods for preparing carbon materials which comprise electrochemicalmodifiers and which comprise high surface area, high porosity and lowlevels of undesirable impurities are not known in the art. Currentmethods for preparing carbon materials of high surface area and highporosity result in carbon materials having high levels of undesirableimpurities. Electrodes prepared by incorporating an electrochemicalmodifier into these carbon materials have poor electrical performance asa result of the residual impurities. Accordingly, in one embodiment thepresent disclosure provides a method for preparing carbon materialscomprising an electrochemical modifier, wherein the carbon materialscomprise a high surface area, high porosity and low levels ofundesirable impurities. In some embodiments, the methods comprisepreparation of a polymer gel by a sol gel process followed by pyrolysisof the dried polymer gel and optional activation of the pyrolyzedpolymer gel. The sol gel process provides significant flexibility suchthat an electrochemical modifier can be incorporated at any number ofsteps. In other embodiments, carbon materials from other sources (e.g.,carbon nanotubes, carbon fibers, etc.) can be impregnated with anelectrochemical modifier. In one embodiment, a method for preparing apolymer gel comprising an electrochemical modifier is provided. Inanother embodiment, methods for preparing pyrolyzed polymer gelscomprising electrochemical modifiers or activated carbon materialscomprising electrochemical modifiers is provided. Details of thevariable process parameters of the various embodiments of the disclosedmethods are described below.

1. Preparation of Polymer Gels

The polymer gels may be prepared by a sol gel process. For example, thepolymer gel may be prepared by co-polymerizing one or more polymerprecursors in an appropriate solvent. In one embodiment, the one or morepolymer precursors are co-polymerized under acidic conditions. In someembodiments, a first polymer precursor is a phenolic compound and asecond polymer precursor is an aldehyde compound. In one embodiment, ofthe method the phenolic compound is phenol, resorcinol, catechol,hydroquinone, phloroglucinol, or a combination thereof; and the aldehydecompound is formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde,benzaldehyde, cinnamaldehyde, or a combination thereof. In a furtherembodiment, the phenolic compound is resorcinol, phenol or a combinationthereof, and the aldehyde compound is formaldehyde. In yet furtherembodiments, the phenolic compound is resorcinol and the aldehydecompound is formaldehyde.

The sol gel polymerization process is generally performed undercatalytic conditions. Accordingly, in some embodiments, preparing thepolymer gel comprises co-polymerizing one or more polymer precursors inthe presence of a catalyst. In some embodiments, the catalyst comprisesa basic volatile catalyst. For example, in one embodiment, the basicvolatile catalyst comprises ammonium carbonate, ammonium bicarbonate,ammonium acetate, ammonium hydroxide, or combinations thereof. In afurther embodiment, the basic volatile catalyst is ammonium carbonate.In another further embodiment, the basic volatile catalyst is ammoniumacetate.

The molar ratio of catalyst to phenolic compound may have an effect onthe final properties of the polymer gel as well as the final propertiesof the carbon materials, for example. Thus, in some embodiments suchcatalysts are used in the range of molar ratios of 5:1 to 2000:1phenolic compound:catalyst. In some embodiments, such catalysts can beused in the range of molar ratios of 20:1 to 200:1 phenoliccompound:catalyst. For example in other embodiments, such catalysts canbe used in the range of molar ratios of 5:1 to 100:1 phenoliccompound:catalyst.

The reaction solvent is another process parameter that may be varied toobtain the desired properties (e.g., surface area, porosity, purity,etc.) of the polymer gels and carbon materials. In some embodiments, thesolvent for preparation of the polymer gel is a mixed solvent system ofwater and a miscible co-solvent. For example, in certain embodiments thesolvent comprises a water miscible acid. Examples of water miscibleacids include, but are not limited to, propionic acid, acetic acid, andformic acid. In further embodiments, the solvent comprises a ratio ofwater-miscible acid to water of 99:1, 90:10, 75:25, 50:50, 25:75, 10:90or 1:90. In other embodiments, acidity is provided by adding a solidacid to the reaction solvent.

In some other embodiments of the foregoing, the solvent for preparationof the polymer gel is acidic. For example, in certain embodiments thesolvent comprises acetic acid. For example, in one embodiment, thesolvent is 100% acetic acid. In other embodiments, a mixed solventsystem is provided, wherein one of the solvents is acidic. For example,in one embodiment of the method the solvent is a binary solventcomprising acetic acid and water. In further embodiments, the solventcomprises a ratio of acetic acid to water of 99:1, 90:10, 75:25, 50:50,25:75, 20:80, 10:90 or 1:90. In other embodiments, acidity is providedby adding a solid acid to the reaction solvent.

Some embodiments of the disclosed method do not comprise a solventexchange step (e.g., exchange t-butanol for water) prior to drying(e.g., lyophilization). For example, in one embodiment of any of themethods described herein, before freezing, the polymer gel or polymergel particles are rinsed with water. In one embodiment, the averagediameter of the polymer gel particles prior to freezing is less than 25mm, for example, between 0.001 mm and 25 mm; alternately, the averagediameter of the polymer gel particles prior to freezing is between 0.01mm and 15 mm, for example, between 1.0 mm and 15 mm. In some examples,the polymer gel particles are between 1 mm and 10 mm. In furtherembodiments, the polymer gel particles are frozen via immersion in amedium having a temperature of below about −10° C., for example, belowabout −20° C., or alternatively below about −30° C. For example, themedium may be liquid nitrogen or ethanol (or other organic solvent) indry ice or ethanol cooled by another means. In some embodiments, dryingunder vacuum comprises subjecting the frozen particles to a vacuumpressure of below about 3000 mTorr. Alternatively, drying under vacuumcomprises subjecting the frozen particles to a vacuum pressure of belowabout 1000 mTorr. Alternatively, drying under vacuum comprisessubjecting the frozen particles to a vacuum pressure of below about 300mTorr. Alternatively, drying under vacuum comprises subjecting thefrozen particles to a vacuum pressure of below about 100 mTorr.

Other methods of rapidly freezing the polymer gel particles are alsoenvisioned. For example, in another embodiment the polymer gel israpidly frozen by co-mingling or physical mixing of polymer gelparticles with a suitable cold solid, for example, dry ice (solid carbondioxide). Another envisioned method comprises using a blast freezer witha metal plate at −60° C. to rapidly remove heat from the polymer gelparticles scattered over its surface. Another method of rapidly coolingwater in a polymer gel particle is to snap freeze the particle bypulling a high vacuum very rapidly (the degree of vacuum is such thatthe temperature corresponding to the equilibrium vapor pressure allowsfor freezing). Yet another method for rapid freezing comprises admixinga polymer gel with a suitably cold gas. In some embodiments the cold gasmay have a temperature below about −10° C. In some embodiments the coldgas may have a temperature below about −20° C. In some embodiments thecold gas may have a temperature below about −30° C. In yet otherembodiments, the gas may have a temperature of about −196° C. Forexample, in some embodiments, the gas is nitrogen. In yet otherembodiments, the gas may have a temperature of about −78° C. Forexample, in some embodiments, the gas is carbon dioxide.

In other embodiments, the polymer gel particles are frozen on alyophilizer shelf at a temperature of −20° C. or lower. For example, insome embodiments the polymer gel particles are frozen on the lyophilizershelf at a temperature of −30° C. or lower. In some other embodiments,the polymer gel monolith is subjected to a freeze thaw cycle (from roomtemperature to −20° C. or lower and back to room temperature), physicaldisruption of the freeze-thawed gel to create particles, and thenfurther lyophilization processing. For example, in some embodiments, thepolymer gel monolith is subjected to a freeze thaw cycle (from roomtemperature to −30° C. or lower and back to room temperature), physicaldisruption of the freeze-thawed gel to create particles, and thenfurther lyophilization processing.

In some embodiments of the methods described herein, the molar ratio ofphenolic precursor to catalyst is from about 5:1 to about 2000:1 or themolar ratio of phenolic precursor to catalyst is from about 20:1 toabout 200:1. In further embodiments, the molar ratio of phenolicprecursor to catalyst is from about 25:1 to about 100:1. In furtherembodiments, the molar ratio of phenolic precursor to catalyst is fromabout 25:1 to about 50:1. In further embodiments, the molar ratio ofphenolic precursor to catalyst is from about 100:1 to about 5:1.

In the specific embodiment wherein one of the polymer precursors isresorcinol and another polymer precursor is formaldehyde, the resorcinolto catalyst ratio can be varied to obtain the desired properties of theresultant polymer gel and carbon materials. In some embodiments of themethods described herein, the molar ratio of resorcinol to catalyst isfrom about 10:1 to about 2000:1 or the molar ratio of resorcinol tocatalyst is from about 20:1 to about 200:1. In further embodiments, themolar ratio of resorcinol to catalyst is from about 25:1 to about 100:1.In further embodiments, the molar ratio of resorcinol to catalyst isfrom about 25:1 to about 50:1. In further embodiments, the molar ratioof resorcinol to catalyst is from about 100:1 to about 5:1.

Polymerization to form a polymer gel can be accomplished by variousmeans described in the art and may include addition of anelectrochemical modifier. For instance, polymerization can beaccomplished by incubating suitable polymer precursor materials, andoptionally an electrochemical modifier, in the presence of a suitablecatalyst for a sufficient period of time. The time for polymerizationcan be a period ranging from minutes or hours to days, depending on thetemperature (the higher the temperature the faster, the reaction rate,and correspondingly, the shorter the time required). The polymerizationtemperature can range from room temperature to a temperature approaching(but lower than) the boiling point of the starting solution. Forexample, the temperature can range from about 20° C. to about 90° C. Inthe specific embodiment wherein one polymer precursor is resorcinol andone polymer precursor is formaldehyde, the temperature can range fromabout 20° C. to about 100° C., typically from about 25° C. to about 90°C. In some embodiments, polymerization can be accomplished by incubationof suitable synthetic polymer precursor materials in the presence of acatalyst for at least 24 hours at about 90° C. Generally polymerizationcan be accomplished in between about 6 and about 24 hours at about 90°C., for example between about 18 and about 24 hours at about 90° C.

The polymer precursor materials as disclosed herein include (a)alcohols, phenolic compounds, and other mono- or polyhydroxy compoundsand (b) aldehydes, ketones, and combinations thereof. Representativealcohols in this context include straight chain and branched, saturatedand unsaturated alcohols. Suitable phenolic compounds includepolyhydroxy benzene, such as a dihydroxy or trihydroxy benzene.Representative polyhydroxy benzenes include resorcinol (i.e.,1,3-dihydroxy benzene), catechol, hydroquinone, and phloroglucinol.Mixtures of two or more polyhydroxy benzenes can also be used. Phenol(monohydroxy benzene) can also be used. Representative polyhydroxycompounds include sugars, such as glucose, and other polyols, such asmannitol. Aldehydes in this context include: straight chain saturatedaldeydes such as methanal (formaldehyde), ethanal (acetaldehyde),propanal (propionaldehyde), butanal (butyraldehyde), and the like;straight chain unsaturated aldehydes such as ethenone and other ketenes,2-propenal (acrylaldehyde), 2-butenal (crotonaldehyde), 3 butenal, andthe like; branched saturated and unsaturated aldehydes; andaromatic-type aldehydes such as benzaldehyde, salicylaldehyde,hydrocinnamaldehyde, and the like. Suitable ketones include: straightchain saturated ketones such as propanone and 2 butanone, and the like;straight chain unsaturated ketones such as propenone, 2 butenone, and3-butenone (methyl vinyl ketone) and the like; branched saturated andunsaturated ketones; and aromatic-type ketones such as methyl benzylketone (phenylacetone), ethyl benzyl ketone, and the like. The polymerprecursor materials can also be combinations of the precursors describedabove.

In some embodiments, one polymer precursor is an alcohol-containingspecies and another polymer precursor is a carbonyl-containing species.The relative amounts of alcohol-containing species (e.g., alcohols,phenolic compounds and mono- or poly-hydroxy compounds or combinationsthereof) reacted with the carbonyl containing species (e.g. aldehydes,ketones or combinations thereof) can vary substantially. In someembodiments, the ratio of alcohol-containing species to aldehyde speciesis selected so that the total moles of reactive alcohol groups in thealcohol-containing species is approximately the same as the total molesof reactive carbonyl groups in the aldehyde species. Similarly, theratio of alcohol-containing species to ketone species may be selected sothat the total moles of reactive alcohol groups in the alcoholcontaining species is approximately the same as the total moles ofreactive carbonyl groups in the ketone species. The same general 1:1molar ratio holds true when the carbonyl-containing species comprises acombination of an aldehyde species and a ketone species.

The total solids content in the solution or suspension prior to polymergel formation can be varied. The weight ratio of resorcinol to water isfrom about 0.05 to 1 to about 0.70 to 1. Alternatively, the ratio ofresorcinol to water is from about 0.15 to 1 to about 0.6 to 1.Alternatively, the ratio of resorcinol to water is from about 0.15 to 1to about 0.35 to 1. Alternatively, the ratio of resorcinol to water isfrom about 0.25 to 1 to about 0.5 to 1. Alternatively, the ratio ofresorcinol to water is from about 0.3 to 1 to about 0.4 to 1.

Examples of solvents useful in the preparation of the polymer gelsdisclosed herein include but are not limited to water or alcohols suchas, for example, ethanol, t butanol, methanol or combinations thereof aswell as aqueous mixtures of the same. Such solvents are useful fordissolution of the polymer precursor materials, for example dissolutionof the phenolic compound. In addition, in some processes such solventsare employed for solvent exchange in the polymer gel (prior to freezingand drying), wherein the solvent from the polymerization of theprecursors, for example, resorcinol and formaldehyde, is exchanged for apure alcohol. In one embodiment of the present application, a polymergel is prepared by a process that does not include solvent exchange.

Suitable catalysts in the preparation of the polymer gels includevolatile basic catalysts that facilitate polymerization of the precursormaterials into a monolithic polymer. The catalyst can also comprisevarious combinations of the catalysts described above. In embodimentscomprising phenolic compounds, such catalysts can be used in the rangeof molar ratios of 5:1 to 200:1 phenolic compound:catalyst. For example,in some specific embodiments such catalysts can be used in the range ofmolar ratios of 25:1 to 100:1 phenolic compound:catalyst.

2. Creation of Polymer Gel Particles

A monolithic polymer gel can be physically disrupted to create smallerparticles according to various techniques known in the art. Theresultant polymer gel particles generally have an average diameter ofless than about 30 mm, for example, in the size range of about 1 mm toabout 25 mm, or between about 1 mm to about 5 mm or between about 0.5 mmto about 10 mm. Alternatively, the size of the polymer gel particles canbe in the range below about 1 mm, for example, in the size range ofabout 10 to 1000 microns. Techniques for creating polymer gel particlesfrom monolithic material include manual or machine disruption methods,such as sieving, grinding, milling, or combinations thereof. Suchmethods are well-known to those of skill in the art. Various types ofmills can be employed in this context such as roller, bead, and ballmills and rotary crushers and similar particle creation equipment knownin the art.

In a specific embodiment, a roller mill is employed. A roller mill hasthree stages to gradually reduce the size of the gel particles. Thepolymer gels are generally very brittle and are not damp to the touch.Consequently they are easily milled using this approach; however, thewidth of each stage must be set appropriately to achieve the targetedfinal mesh. This adjustment is made and validated for each combinationof gel recipe and mesh size. Each gel is milled via passage through asieve of known mesh size. Sieved particles can be temporarily stored insealed containers.

In one embodiment, a rotary crusher is employed. The rotary crusher hasa screen mesh size of about 118^(th) inch. In another embodiment, therotary crusher has a screen mesh size of about 318^(th) inch. In anotherembodiment, the rotary crusher has a screen mesh size of about 518^(th)inch. In another embodiment, the rotary crusher has a screen mesh sizeof about 318^(th) inch.

Milling can be accomplished at room temperature according to methodswell known to those of skill in the art. Alternatively, milling can beaccomplished cryogenically, for example by co-milling the polymer gelwith solid carbon dioxide (dry ice) particles. In this embodiment, thetwo steps of (a) creating particles from the monolithic polymer gel and(b) rapid, multidirectional freezing of the polymer gel are accomplishedin a single process.

3. Rapid Freezing of Polymer Gels

After the polymer gel particles are formed from the monolithic polymergel, freezing of the polymer gel particles may be accomplished rapidlyand in a multi-directional fashion as described in more detail above.Freezing slowly and in a unidirectional fashion, for example by shelffreezing in a lyophilizer, results in dried material having a very lowsurface area. Similarly, snap freezing (i.e., freezing that isaccomplished by rapidly cooling the polymer gel particles by pulling adeep vacuum) also results in a dried material having a low surface area.As disclosed herein rapid freezing in a multidirectional fashion can beaccomplished by rapidly lowering the material temperature to at leastabout −10° C. or lower, for example, −20° C. or lower, or for example,to at least about −30° C. or lower. Rapid freezing of the polymer gelparticles creates a fine ice crystal structure within the particles dueto widespread nucleation of ice crystals, but leaves little time for icecrystal growth. This provides a high specific surface area between theice crystals and the hydrocarbon matrix, which is necessarily excludedfrom the ice matrix.

The concept of extremely rapid freezing to promote nucleation overcrystal growth can also be applied to mixed solvent systems. In oneembodiment, as the mixed solvent system is rapidly cooled, the solventcomponent that predominates will undergo crystallization at itsequilibrium melting temperature, with increased concentration of theco-solvent(s) and concomitant further freezing point depression. As thetemperature is further lowered, there is increased crystallization ofthe predominant solvent and concentration of co-solvent(s) until theeutectic composition is reached, at which point the eutectic compositionundergoes the transition from liquid to solid without further componentconcentration or product cooling until complete freezing is achieved. Inthe specific case of water and acetic acid (which as pure substancesexhibit freezing points of 0° C. and 17° C., respectively), the eutecticcomposition is comprised of approximately 59% acetic acid and 41% waterand freezes at about −27° C. Accordingly, in one embodiment, the mixedsolvent system is the eutectic composition, for example, in oneembodiment the mixed solvent system comprises 59% acetic acid and 41%water.

4. Drying of Polymer Gels

In one embodiment, the frozen polymer gel particles containing a fineice matrix are lyophilized under conditions designed to avoid collapseof the material and to maintain fine surface structure and porosity inthe dried product. Generally drying is accomplished under conditionswhere the temperature of the product is kept below a temperature thatwould otherwise result in collapse of the product pores, therebyenabling the dried material to retain an extremely high surface area.

The structure of the final carbon material is reflected in the structureof the dried polymer gel which in turn is established by the polymer gelproperties. These features can be created in the polymer gel using asol-gel processing approach as described herein, but if care is nottaken in removal of the solvent, then the structure is not preserved. Itis of interest to both retain the original structure of the polymer geland modify its structure with ice crystal formation based on control ofthe freezing process. In some embodiments prior to drying, the aqueouscontent of the polymer gel is in the range of about 50% to about 99%. Incertain embodiments upon drying, the aqueous content of the polymercryogel is about 10%, alternately less than about 5% or less than about2.5%.

A lyophilizer chamber pressure of about 2250 microns results in aprimary drying temperature in the drying product of about −10° C. Dryingat about 2250 micron chamber pressure or lower case provides a producttemperature during primary drying that is no greater than about −10° C.As a further illustration, a chamber pressure of about 1500 micronsresults in a primary drying temperature in the drying product of about−15° C. Drying at about 1500 micron chamber pressure or lower provides aproduct temperature during primary drying that is no greater than about−15° C. As yet a further illustration, a chamber pressure of about 750microns results in a primary drying temperature in the drying product ofabout −20° C. Drying at 750 micron chamber pressure or lower provides aproduct temperature during primary drying that is no greater than about−20° C. As yet a further illustration, a chamber pressure of about 300microns results in a primary drying temperature in the drying product ofabout −30° C. Drying at 300 micron chamber pressure or lower provides aproduct temperature during primary drying that is no greater than about−30° C.

5. Pyrolysis and Activation of Polymer Gels

The polymer gels described above, can be further processed to obtaincarbon materials. Such processing includes, for example, pyrolysisand/or activation. Generally, in the pyrolysis process, dried polymergels are weighed and placed in a rotary kiln. The temperature ramp isset at 5° C. per minute, the dwell time and dwell temperature are set;cool down is determined by the natural cooling rate of the furnace. Theentire process is usually run under an inert atmosphere, such as anitrogen environment. Pyrolyzed samples are then removed and weighed.Other pyrolysis processes are well known to those of skill in the art.

In some embodiments, pyrolysis dwell time (the period of time duringwhich the sample is at the desired temperature) is from about 0 minutesto about 120 minutes, from about 0 minutes to about 60 minutes, fromabout 0 minutes to about 30 minutes, from about 0 minutes to about 10minutes, from about 0 to 5 minutes or from about 0 to 1 minute.

Pyrolysis may also be carried out more slowly than described above. Forexample, in one embodiment the pyrolysis is carried out in about 120 to480 minutes. In other embodiments, the pyrolysis is carried out in about120 to 240 minutes.

In some embodiments, pyrolysis dwell temperature ranges from about 500°C. to 2400° C. In some embodiments, pyrolysis dwell temperature rangesfrom about 650° C. to 1800° C. In other embodiments pyrolysis dwelltemperature ranges from about 700° C. to about 1200° C. In otherembodiments pyrolysis dwell temperature ranges from about 850° C. toabout 1050° C. In other embodiments pyrolysis dwell temperature rangesfrom about 800° C. to about 900° C.

In some embodiments, the pyrolysis dwell temperature is varied duringthe course of pyrolysis. In one embodiment, the pyrolysis is carried outin a rotary kiln with separate, distinct heating zones. The temperaturefor each zone is sequentially decreased from the entrance to the exitend of the rotary kiln tube. In one embodiment, the pyrolysis is carriedout in a rotary kiln with separate distinct heating zones, and thetemperature for each zone is sequentially increased from entrance toexit end of the rotary kiln tube.

Activation time and activation temperature both have a large impact onthe performance of the resulting activated carbon material, as well asthe manufacturing cost thereof. Increasing the activation temperatureand the activation dwell time results in higher activation percentages,which generally correspond to the removal of more material compared tolower temperatures and shorter dwell times. Activation temperature canalso alter the pore structure of the carbon where lower temperaturesresult in more microporous carbon and higher temperatures result inmesoporosity. This is a result of the activation gas diffusion limitedreaction that occurs at higher temperatures and reaction kinetic drivenreactions that occur at lower temperature. Higher activation percentageoften increases performance of the final activated carbon, but it alsoincreases cost by reducing overall yield. Improving the level ofactivation corresponds to achieving a higher performance product at alower cost.

Pyrolyzed polymer gels may be activated by contacting the pyrolyzedpolymer gel with an activating agent. Many gases are suitable foractivating, for example gases which contain oxygen. Non-limitingexamples of activating gases include carbon dioxide, carbon monoxide,steam, oxygen and combinations thereof. Activating agents may alsoinclude corrosive chemicals such as acids, bases or salts (e.g.,phosphoric acid, acetic acid, citric acid, formic acid, oxalic acid,uric acid, lactic acid, potassium hydroxide, sodium hydroxide, zincchloride, etc.). Other activating agents are known to those skilled inthe art.

In some embodiments, the activation time is between 1 minute and 48hours. In other embodiments, the activation time is between 1 minute and24 hours. In other embodiments, the activation time is between 5 minutesand 24 hours. In other embodiments, the activation time is between 1hour and 24 hours. In further embodiments, the activation time isbetween 12 hours and 24 hours. In certain other embodiments, theactivation time is between 30 min and 4 hours. In some furtherembodiments, the activation time is between 1 hour and 2 hours.

Pyrolyzed polymer gels may be activated using any number of suitableapparatuses known to those skilled in the art, for example, fluidizedbeds, rotary kilns, elevator kilns, roller hearth kilns, pusher kilns,etc. In one embodiment of the activation process, samples are weighedand placed in a rotary kiln, for which the automated gas controlmanifold is set to ramp at a 20° C. per minute rate. Carbon dioxide isintroduced to the kiln environment for a period of time once the properactivation temperature has been reached. After activation has occurred,the carbon dioxide is replaced by nitrogen and the kiln is cooled down.Samples are weighed at the end of the process to assess the level ofactivation. Other activation processes are well known to those of skillin the art. In some of the embodiments disclosed herein, activationtemperatures may range from 800° C. to 1300° C. In another embodiment,activation temperatures may range from 800° C. to 1050° C. In anotherembodiment, activation temperatures may range from about 850° C. toabout 950° C. One skilled in the art will recognize that otheractivation temperatures, either lower or higher, may be employed.

The degree of activation is measured in terms of the mass percent of thepyrolyzed dried polymer gel that is lost during the activation step. Inone embodiment of the methods described herein, activating comprises adegree of activation from 5% to 90%; or a degree of activation from 10%to 80%; in some cases activating comprises a degree of activation from40% to 70%, or a degree of activation from 45% to 65%.

C. Characterization of Polymer Gels and Carbon Materials

The structural properties of the final carbon material and intermediatepolymer gels may be measured using Nitrogen sorption at 77K, a methodknown to those of skill in the art. The final performance andcharacteristics of the finished carbon material is important, but theintermediate products (both dried polymer gel and pyrolyzed, but notactivated, polymer gel), can also be evaluated, particularly from aquality control standpoint, as known to those of skill in the art. TheMicromeretics ASAP 2020 is used to perform detailed micropore andmesopore analysis, which reveals a pore size distribution from 0.35 nmto 50 nm in some embodiments. The system produces a nitrogen isothermstarting at a pressure of 10⁻⁷ atm, which enables high resolution poresize distributions in the sub 1 nm range. The software generated reportsutilize a Density Functional Theory (DFT) method to calculate propertiessuch as pore size distributions, surface area distributions, totalsurface area, total pore volume, and pore volume within certain poresize ranges.

The impurity content of the carbon materials can be determined by anynumber of analytical techniques known to those of skill in the art. Oneparticular analytical method useful within the context of the presentdisclosure is proton induced x-ray emission (PIXE). This technique iscapable of measuring the concentration of elements having atomic numbersranging from 11 to 92 at low ppm levels. Accordingly, in one embodimentthe concentration of impurities present in the carbon materials isdetermined by PIXE analysis.

D. Devices Comprising the Carbon Materials

1. EDLCs

The disclosed carbon materials can be used as electrode material in anynumber of electrical energy storage and distribution devices. One suchdevice is an ultracapacitor. Ultracapacitors comprising carbon materialsare described in detail in co-owned U.S. Pat. No. 7,835,136 which ishereby incorporated in its entirety.

EDLCs use electrodes immersed in an electrolyte solution as their energystorage element. Typically, a porous separator immersed in andimpregnated with the electrolyte ensures that the electrodes do not comein contact with each other, preventing electronic current flow directlybetween the electrodes. At the same time, the porous separator allowsionic currents to flow through the electrolyte between the electrodes inboth directions thus forming double layers of charges at the interfacesbetween the electrodes and the electrolyte.

When electric potential is applied between a pair of electrodes of anEDLC, ions that exist within the electrolyte are attracted to thesurfaces of the oppositely-charged electrodes, and migrate towards theelectrodes. A layer of oppositely-charged ions is thus created andmaintained near each electrode surface. Electrical energy is stored inthe charge separation layers between these ionic layers and the chargelayers of the corresponding electrode surfaces. In fact, the chargeseparation layers behave essentially as electrostatic capacitors.Electrostatic energy can also be stored in the EDLCS through orientationand alignment of molecules of the electrolytic solution under influenceof the electric field induced by the potential. This mode of energystorage, however, is secondary.

EDLCS comprising the disclosed carbon material can be employed invarious electronic devices where high power is desired. Accordingly, inone embodiment an electrode comprising the carbon materials is provided.In another embodiment, the electrode comprises activated carbonmaterial. In a further embodiment, an ultracapacitor comprising anelectrode comprising the carbon materials is provided. In a furtherembodiment of the foregoing, the ultrapure synthetic carbon materialcomprises an optimized balance of micropores and mesopores and describedabove.

The disclosed carbon materials find utility in any number of electronicdevices, for example wireless consumer and commercial devices such asdigital still cameras, notebook PCs, medical devices, location trackingdevices, automotive devices, compact flash devices, mobiles phones,PCMCIA cards, handheld devices, and digital music players.Ultracapacitors are also employed in heavy equipment such as: excavatorsand other earth moving equipment, forklifts, garbage trucks, cranes forports and construction and transportation systems such as buses,automobiles and trains.

Accordingly, in certain embodiments the present disclosure provides anelectrical energy storage device comprising any of the foregoing carbonmaterials, for example a carbon material comprising a pore structure,the pore structure comprising micropores, mesopores and a total porevolume, wherein from 20% to 80% of the total pore volume resides inmicropores and from 20% to 80% of the total pore volume resides inmesopores and less than 10% of the total pore volume resides in poresgreater than 20 nm.

In some embodiments, the device is an electric double layer capacitor(EDLC) device comprising:

a) a positive electrode and a negative electrode wherein each of thepositive and the negative electrodes comprise the carbon material;

b) an inert porous separator; and

c) an electrolyte;

wherein the positive electrode and the negative electrode are separatedby the inert porous separator.

In one embodiment, an ultracapacitor device comprising the carbonmaterial comprises a gravimetric power of at least 5 W/g, at least 10W/g, at least 15 W/g, at least 20 W/g, at least 25 W/g, at least 30 W/g,at least 35 W/g, at least 50 W/g. In another embodiment, anultracapacitor device comprising the carbon material comprises avolumetric power of at least 2 W/g, at least 4 W/cc, at least 5 W/cc, atleast 10 W/cc, at least 15 W/cc or at least 20 W/cc. In anotherembodiment, an ultracapacitor device comprising the carbon materialcarbon material comprises a gravimetric energy of at least 2.5 Wh/kg, atleast 5.0 Wh/kg, at least 7.5 Wh/kg, at least 10 Wh/kg, at least 12.5Wh/kg, at least 15.0 Wh/kg, at least 17.5. Wh/kg, at least 20.0 Wh/kg,at least 22.5 wh/kg or at least 25.0 Wh/kg. In another embodiment, anultracapacitor device comprising the carbon material comprises avolumetric energy of at least 1.5 Wh/liter, at least 3.0 Wh/liter, atleast 5.0 Wh/liter, at least 7.5 Wh/liter, at least 10.0 Wh/liter, atleast 12.5 Wh/liter, at least 15 Wh/liter, at least 17.5 Wh/liter or atleast 20.0 Wh/liter.

In some embodiments of the foregoing, the gravimetric power, volumetricpower, gravimetric energy and volumetric energy of an ultracapacitordevice comprising the carbon material are measured by constant currentdischarge from 2.7 V to 1.89 V employing a 1.0 M solution oftetraethylammonium-tetrafluroroborate in acetonitrile (1.0 M TEATFB inAN) electrolyte and a 0.5 second time constant.

In one embodiment, an ultracapacitor device comprising the carbonmaterial comprises a gravimetric power of at least 10 W/g, a volumetricpower of at least 5 W/cc, a gravimetric capacitance of at least 100 F/g(@0.5 A/g) and a volumetric capacitance of at least 10 F/cc (@0.5 A/g).In one embodiment, the aforementioned ultracapacitor device is a coincell double layer ultracapacitor comprising the carbon material, aconductivity enhancer, a binder, an electrolyte solvent, and anelectrolyte salt. In further embodiments, the aforementionedconductivity enhancer is a carbon black and/or other conductivityenhancer known in the art. In further embodiments, the aforementionedbinder is Teflon and or other binder known in the art. In furtheraforementioned embodiments, the electrolyte solvent is acetonitrile orpropylene carbonate, or other electrolyte solvent(s) known in the art.In further aforementioned embodiments, the electrolyte salt istetraethylaminotetrafluroborate or triethylmethyl aminotetrafluroborateor other electrolyte salt known in the art, or liquid electrolyte knownin the art.

In one embodiment, an ultracapacitor device comprising the carbonmaterial comprises a gravimetric power of at least 15 W/g, a volumetricpower of at least 10 W/cc, a gravimetric capacitance of at least 110 F/g(@0.5 A/g) and a volumetric capacitance of at least 15 F/cc (@0.5 A/g).In one embodiment, the aforementioned ultracapacitor device is a coincell double layer ultracapacitor comprising the carbon material, aconductivity enhancer, a binder, an electrolyte solvent, and anelectrolyte salt. In further embodiments, the aforementionedconductivity enhancer is a carbon black and/or other conductivityenhancer known in the art. In further embodiments, the aforementionedbinder is Teflon and or other binder known in the art. In furtheraforementioned embodiments, the electrolyte solvent is acetonitrile orpropylene carbonate, or other electrolyte solvent(s) known in the art.In further aforementioned embodiments, the electrolyte salt istetraethylaminotetrafluroborate or triethylmethyl aminotetrafluroborateor other electrolyte salt known in the art, or liquid electrolyte knownin the art.

In one embodiment, an ultracapacitor device comprising the carbonmaterial comprises a gravimetric capacitance of at least 90 F/g, atleast 95 F/g, at least 100 F/g, at least 105 F/g, at least 110 F/g, atleast 115 F/g, at least 120 F/g, at least 125 F/g, or at least 130 F/g.In another embodiment, an ultracapacitor device comprising the carbonmaterial comprises a volumetric capacitance of at least 5 F/cc, at least10 F/cc, at least 15 F/cc, at least 20 F/cc, or at least 25 F/cc. Insome embodiments of the foregoing, the gravimetric capacitance andvolumetric capacitance are measured by constant current discharge from2.7 V to 0.1 V with a 5-second time constant and employing a 1.8 Msolution of tetraethylammonium-tetrafluroroborate in acetonitrile (1.8 MTEATFB in AN) electrolyte and a current density of 0.5 A/g, 1.0 A/g, 4.0A/g or 8.0 A/g.

In one embodiment, the present disclosure provides ultracapacitorscomprising a carbon material as disclosed herein, wherein the percentdecrease in original capacitance (i.e., capacitance before beingsubjected to voltage hold) of the ultracapacitor comprising the carbonmaterial after a voltage hold period is less than the percent decreasein original capacitance of an ultracapacitor comprising known carbonmaterials. In one embodiment, the percent of original capacitanceremaining for an ultracapacitor comprising the carbon material after avoltage hold at 2.7 V for 24 hours at 65° C. is at least 90%, at least80%, at least 70%, at least 60%, at least 50%, at least 40%, at least30% at least 20% or at least 10%. In further embodiments of theforegoing, the percent of original capacitance remaining after thevoltage hold period is measured at a current density of 0.5 A/g, 1 A/g,4 A/g or 8 A/g.

In another embodiment, the present disclosure provides ultracapacitorscomprising a carbon material as disclosed herein, wherein the percentdecrease in original capacitance of the ultracapacitor comprising thecarbon material after repeated voltage cycling is less than the percentdecrease in original capacitance of an ultracapacitor comprising knowncarbon materials subjected to the same conditions. For example, in oneembodiment, the percent of original capacitance remaining for anultracapacitor comprising the carbon material is more than the percentof original capacitance remaining for an ultracapacitor comprising knowncarbon materials after 1000, 2000, 4000, 6000, 8000, or 1000 voltagecycling events comprising cycling between 2 V and 1V at a currentdensity of 4 A/g. In another embodiment, the percent of originalcapacitance remaining for an ultracapacitor comprising the carbonmaterial after 1000, 2000, 4000, 6000, 8000, or 1000 voltage cyclingevents comprising cycling between 2 V and 1V at a current density of 4A/g, is at least 90%, at least 80%, at least 70%, at least 60%, at least50%, at least 40%, at least 30% at least 20% or at least 10%.

In still other embodiments, the EDLC device comprises a gravimetriccapacitance of at least of at least 13 F/cc as measured by constantcurrent discharge from 2.7 V to 0.1 V and with at least 0.24 Hzfrequency response and employing a 1.8 M solution oftetraethylammonium-tetrafluroroborate in acetonitrile electrolyte and acurrent density of 0.5 A/g. Other embodiments include and EDLC device,wherein the EDLC device comprises a gravimetric capacitance of at leastof at least 17 F/cc as measured by constant current discharge from 2.7 Vto 0.1 V and with at least 0.24 Hz frequency response and employing a1.8 M solution of tetraethylammonium-tetrafluroroborate in acetonitrileelectrolyte and a current density of 0.5 A/g.

As noted above, the carbon material can be incorporated intoultracapacitor devices. In some embodiments, the carbon material ismilled to an average particle size of about 10 microns using a jetmillaccording to the art. While not wishing to be bound by theory, it isbelieved that this fine particle size enhances particle-to-particleconductivity, as well as enabling the production of very thin sheetelectrodes. The jetmill essentially grinds the carbon against itself byspinning it inside a disc shaped chamber propelled by high-pressurenitrogen. As the larger particles are fed in, the centrifugal forcepushes them to the outside of the chamber; as they grind against eachother, the particles migrate towards the center where they eventuallyexit the grinding chamber once they have reached the appropriatedimensions.

In further embodiments, after jet milling the carbon is blended with afibrous Teflon binder (3% by weight) to hold the particles together in asheet. The carbon Teflon mixture is kneaded until a uniform consistencyis reached. Then the mixture is rolled into sheets using a high-pressureroller-former that results in a final thickness of 50 microns. Theseelectrodes are punched into discs and heated to 195° C. under a dryargon atmosphere to remove water and/or other airbourne contaminants.The electrodes are weighed and their dimensions measured using calipers.

The carbon electrodes of the EDLCs are wetted with an appropriateelectrolyte solution. Examples of solvents for use in electrolytesolutions for use in the devices of the present application include butare not limited to propylene carbonate, ethylene carbonate, butylenecarbonate, dimethyl carbonate, methyl ethyl carbonate, diethylcarbonate, sulfolane, methylsulfolane and acetonitrile. Such solventsare generally mixed with solute, including, tetralkylammonium salts suchas TEATFB (tetraethylammonium tetrafluoroborate); TEMATFB(tri-ethyl,methylammonium tetrafluoroborate); EMITFB(1-ethyl-3-methylimidazolium tetrafluoroborate), tetramethylammonium ortriethylammonium based salts. Further the electrolyte can be a waterbased acid or base electrolyte such as mild sulfuric acid or potassiumhydroxide.

In some embodiments, the electrodes are wetted with a 1.0 M solution oftetraethylammonium-tetrafluroroborate in acetonitrile (1.0 M TEATFB inAN) electrolyte. In other embodiments, the electrodes are wetted with a1.0 M solution of tetraethylammonium-tetrafluroroborate in propylenecarbonate (1.0 M TEATFB in PC) electrolyte. These are commonelectrolytes used in both research and industry and are consideredstandards for assessing device performance. In other embodiments, thesymmetric carbon-carbon (C—C) capacitors are assembled under an inertatmosphere, for example, in an Argon glove box, and a NKK porousmembrane 30 micron thick serves as the separator. Once assembled, thesamples may be soaked in the electrolyte for about 20 minutes or moredepending on the porosity of the sample.

In some embodiments, the capacitance and power output are measured usingcyclic voltametry (CV), chronopotentiometry (CP) and impedancespectroscopy at various voltages (ranging from 1.0-2.5 V maximumvoltage) and current levels (from 1-10 mA) on a Biologic VMP3electrochemical workstation. In this embodiment, the capacitance may becalculated from the discharge curve of the potentiogram using theformula:

$\begin{matrix}{C = \frac{I \times \Delta \; t}{\Delta \; V}} & {{Equation}\mspace{14mu} 1}\end{matrix}$

where I is the current (A) and ΔV is the voltage drop, Δt is the timedifference. Because in this embodiment the test capacitor is a symmetriccarbon-carbon (C—C) electrode, the specific capacitance is determinedfrom:

C _(s)=2C/m _(e)  Equation 2

where m_(e) is the mass of a single electrode. The specific energy andpower may be determined using:

$\begin{matrix}{E_{s} = {\frac{1}{4}\frac{{CV}_{\max}^{2}}{m_{e}}}} & {{Equation}\mspace{14mu} 3} \\{P_{s} = {{E_{s}/4}{ESR}}} & {{Equation}\mspace{14mu} 4}\end{matrix}$

where C is the measured capacitance V_(max) is the maximum test voltageand ESR is the equivalent series resistance obtained from the voltagedrop at the beginning of the discharge. ESR can alternately be derivedfrom impedance spectroscopy.

2. Batteries

The disclosed carbon materials also find utility as electrodes in a anynumber of types of batteries. One such battery is the metal air battery,for example lithium air batteries. Lithium air batteries generallycomprise an electrolyte interposed between positive electrode andnegative electrodes. The positive electrode generally comprises alithium compound such as lithium oxide or lithium peroxide and serves tooxidize or reduce oxygen. The negative electrode generally comprises acarbonaceous substance which absorbs and releases lithium ions. As withsupercapacitors, batteries such as lithium air batteries which comprisethe disclosed carbon materials are expected to be superior to batteriescomprising known carbon materials. Accordingly, in one embodiment thepresent invention provides a metal air battery, for example a lithiumair battery, comprising a carbon material as disclosed herein.

Any number of other batteries, for example, zinc-carbon batteries,lithium/carbon batteries, lead acid batteries and the like are alsoexpected to perform better with the carbon materials. One skilled in theart will recognize other specific types of carbon containing batterieswhich will benefit from the disclosed carbon materials. Accordingly, inanother embodiment the present invention provides a battery, inparticular a zinc/carbon, a lithium/carbon batteries or a lead acidbattery comprising a carbon material as disclosed herein.

One embodiment is directed to a lead acid battery comprising thedisclosed carbon materials, for example a lead/acid battery comprising:

a) at least one positive electrode comprising a first active material inelectrical contact with a first current collector;

b) at least one negative electrode comprising a second active materialin electrical contact with a second current collector; and

c) an electrolyte;

wherein the positive electrode and the negative electrode are separatedby an inert porous separator, and wherein at least one of the first orsecond active materials comprises the carbon material.

Active materials within the scope of the present disclosure includematerials capable of storing and/or conducting electricity. The activematerial can be any active material known in the art and useful in leadacid batteries, for example the active material may comprise lead, lead(II) oxide, lead (IV) oxide, or combinations thereof and may be in theform of a paste.

Another embodiment of any of the above devices, the carbon materialcomprises the same micropore to mesopore distribution but at a lowersurface area range. This embodiment is prepared by synthesizing the samebase high purity polymer structure that yields the same optimizedmicropore to mesopore volume distribution with low surface functionalityupon pyrolysis (but no activation). The result of lower surface areaoptimized pore structure in a battery application like lead acidbatteries is a maximization of an electrode formulation with a highlyconductive network. It is also theorized that high mesopore volume maybe an excellent structure to allow high ion mobility in many otherenergy storage systems such as lead acid, lithium ion, etc.

EXAMPLES

The carbon materials disclosed in the following Examples were preparedaccording to the methods disclosed herein. Chemicals were obtained fromcommercial sources at reagent grade purity or better and were used asreceived from the supplier without further purification.

Unless indicated otherwise, the following conditions were generallyemployed for preparation of the carbon materials and precursors.Phenolic compound and aldehyde were reacted in the presence of acatalyst in a binary solvent system (e.g., water and acetic acid). Themolar ratio of phenolic compound to aldehyde was typically 0.5 to 1. Thereaction was allowed to incubate in a sealed container at temperaturesof up to 85 C for up to 24 h. The resulting polymer hydrogel containedwater, but no organic solvent; and was not subjected to solvent exchangeof water for an organic solvent, such as t-butanol. The polymer hydrogelmonolith was then physically disrupted, for example by grinding, to formpolymer hydrogel particles having an average diameter of less than about5 mm. Unless stated otherwise, the particles were then rapidly frozen,generally by immersion in a cold fluid (e.g., liquid nitrogen orethanol/dry ice) and lyophilized. Generally, the lyophilizer shelf waspre-cooled to −30° C. before loading a tray containing the frozenpolymer hydrogel particles on the lyophilizer shelf. The chamberpressure for lyophilization was typically in the range of 50 to 1000mTorr and the shelf temperature was in the range of +10 to +25° C.Alternatively, the shelf temperature can be set lower, for example inthe range of 0 to +10° C. Alternatively, the shelf temperature can beset higher, for example in the range of 25 to +100° C. Chamber pressurecan be held in the range of 50 to 3000 mTorr. For instance, the chamberpressure can be controlled in the range of 150 to 300 mTorr.

The dried polymer hydrogel was typically pyrolyzed by heating in anitrogen atmosphere at temperatures ranging from 700-1200° C. for aperiod of time as specified in the examples. Activation conditionsgenerally comprised heating a pyrolyzed polymer hydrogel in a CO₂atmosphere at temperatures ranging from 800-1000° C. for a period oftime as specified in the examples. Specific pyrolysis and activationconditions were as described in the following examples.

Example 1 Preparation of Dried Polymer Gel

A polymer gel was prepared by polymerization of resorcinol andformaldehyde (0.5:1) in a water/acetic acid solvent (75:25) in thepresence of ammonium acetate catalyst. The resorcinol to solvent ration(R/S) was 0.3, and the resorcinol to catalyst ratio (R/C) was 25. Thereaction mixture was placed at elevated temperature (incubation at 45°C. for about 6 h followed by incubation at 85° C. for about 24 h) toallow for gellation to create a polymer gel. Polymer gel particles werecreated from the polymer gel and passed through a 4750 micron meshsieve. The sieved particles were flash frozen by immersion in liquidnitrogen, loaded into a lyophilization tray at a loading of 3 to 7g/in², and lyophilized at approximately 50 mTorr. The time to dry (asinferred from time for product to reach within 2° C. of shelftemperature) varied with product loading on the lyophilizer shelf.

The mass loss on drying the polymer gel was 73.4%. The surface area ofthe dried polymer gel was determined to be 752 m²/g, the total porevolume was 1.40 cc/g and the tap density was 0.22 g/cc. The pore sizedistribution of two different batches of dried polymer gel is shown inFIG. 1.

Example 2 Preparation of Pyrolyzed Carbon Material from Dried PolymerGel

Dried polymer gel prepared according to Example 2 was pyrolyzed bypassage through a rotary kiln at 850° C. with a nitrogen gas flow of 200L/h. The weight loss upon pyrolysis was determined to be 56.2%

The surface area of the pyrolyzed dried polymer gel was examined bynitrogen surface analysis using a surface area and porosity analyzer.The measured specific surface area using the standard BET approach was726 m²/g, the total pore volume was 0.71 cc/g and the tap density was0.42 g/cc. Carbon materials comprising different properties (e.g.,surface area, pore structure, etc.) can be prepared by altering thepyrolysis conditions (e.g., temperature, time, etc.) described above.

Example 3 Production of Activated Carbon

Pyrolyzed carbon material prepared according to Example 2 was activateda batch rotary kiln at 900° C. under a CO₂ for 660 min, resulting in atotal weight loss of 64.8%.

The surface area of the activated carbon was examined by nitrogensurface analysis using a surface area and porosity analyzer. Themeasured specific surface area using the BET approach was 1989 m²/g, thetotal pore volume was 1.57 cc/g and the tap density was 0.28 g/cc.

FIG. 2 shows an overlay of the pore size distributions of the pyrolyzedcarbon material of Example 2 and the activated carbon material ofExample 3. Note that the pore size distribution for the activated carbonwas measured on a micromeritics ASAP2020, a micropore-capable analyzerwith a higher resolution (lower pore size volume detection) than theTristar 3020 that was used to measure the pore size distribution for thepyrolyzed carbon.

From the DFT cumulative volume plot for the activated carbon material ofExample 3, it was determined that the 44% of the pore volume resides inmicropores and 56% of the pore volume resides in mesopores. Carbonmaterials comprising different properties (e.g., surface area, porestructure, etc.) can be prepared by altering the activation conditions(e.g., temperature, time, etc.) described above.

Example 4 Micronization of Activated Carbon Via Jet Milling

Activated carbon prepared according to Example 3 was jet milled using aJet Pulverizer Micron Master 2 inch diameter jet mill. The conditionscomprised about 0.7 lbs of activated carbon per hour, nitrogen gas flowabout 20 scf per min and about 100 psi pressure. The average particlesize after jet milling was about 8 to 10 microns.

Example 5 Purity Analysis of Activated Carbon & Comparison Carbons

Carbon samples prepared according to the general procedures herein wereexamined for their impurity content via proton induced x-ray emission(PIXE). PIXE is an industry-standard, highly sensitive and accuratemeasurement for simultaneous elemental analysis by excitation of theatoms in a sample to produce characteristic X-rays which are detectedand their intensities identified and quantified. PIXE is capable ofdetection of all elements with atomic numbers ranging from 11 to 92(i.e., from sodium to uranium).

The PIXE impurities (Imp.) detected in carbon materials as disclosedherein as well as other commercial carbon materials for comparisonpurposes is presented in Table 1. Carbon 1 is a pyrolyzed (but notactivated) carbon material. Carbons 2 and 3 are pyrolyzed and activatedcarbon materials. Carbon 4 is an activated carbon denoted “MSP-20”obtained from Kansai Coke and Chemicals Co., Ltd. (Kakogawa, Japan),Carbon 5 is an activated carbon denoted “YP-50F(YP-17D)” obtained fromKuraray Chemical Co. (Osaka, Japan).

As seen in Table 1, the carbon materials according to the instantdisclosure have a lower PIXE impurity content and lower ash content ascompared to other known activated carbon samples.

TABLE 1 Purity Analysis of Activated Carbon & Comparison CarbonsImpurity Concentration (PPM) Impurity Carbon 1 Carbon 2 Carbon 3 Carbon4 Carbon 5 Na ND* ND ND 353.100 ND Mg ND ND ND 139.000 ND Al ND ND ND63.850 38.941 Si ND ND ND 34.670 513.517 P ND ND ND ND 59.852 S 12.19110.390 18.971 90.110 113.504 Cl ND ND ND 28.230 9.126 K ND ND ND 44.21076.953 Ca 10.651 3.071 16.571 ND 119.804 Cr ND ND ND 4.310 3.744 Mn NDND ND ND 7.552 Fe 2.672 2.144 3.140 3.115 59.212 Ni ND ND ND 36.6202.831 Cu ND ND ND 7.927 17.011 Zn ND ND ND ND 2.151 Total 25.514 15.60538.682 805.142 1024.198 (% Ash) (0.006) (0.003) (0.009) (0.13) (0.16)*ND = not detected by PIXE analysis

Example 6 Preparation and Properties of Various Carbon Samples

As noted above, the disclosed carbon materials comprise a higher densitythrough optimization of the micropore and mesopore structure.Specifically, the carbon material exhibits two regions of porestructures (1) micropores, <20 Å, (2) mesopores between 20 Å and 200 Å.There is a relative lack of pore structure between these twopopulations, and a relative lack of pore structure above 200 Å. Highpulse power EDLC systems require low resistance performance from carbonelectrodes and from the total cell system. This high pulse powerperformance electrode carbon is characterized by fast response time asmeasured using impedance spectroscopy. The fast response time isattributed to purity and pore volume that provide high ion mobility andlow ion resistance within the porous structure.

To demonstrate the utility of the carbon materials, various carbonsamples were prepared by following the general procedures described inExamples 1-4. The physiochemical properties of three different types ofcarbon samples (Carbons 1-3) prepared according to the above proceduresare tabulated in Table 1 below. The pore size distribution of the carbonsamples is depicted in FIG. 3.

TABLE 1 Physiochemical Characteristics of Carbons 1-3 Ratio N₂ PV TotalPore Tap adsorbed meso/ SSA Volume Density (P/Po)95/(P/ PV total Sample(m²/g) (cc/g) (g/cc) Po)5 (%) Purity Carbon 1 600-800 0.6-0.8 0.35-0.452.5-3.5 70-80%* <200 ppm impurities Ash <0.1% Carbon 2 1550-2100 1.2-1.60.25-0.35 2.0-2.5 52-60% <200 ppm impurities Ash <0.1% Carbon 32100-2800 1.5-2.7 0.19-0.28 2.0-2.5 52-60% <200 ppm impurities Ash <0.1%*Calculation from DFT model on Tristar mesopore analysis as opposed toASAP2020 micropore analysis for Carbon 2 & 3.

Example 7 Electrochemical Properties of Various Carbon Samples

The carbon samples were analyzed for their electrochemical performance,specifically as an electrode material in EDLC coin cell devices.Specific details regarding fabrication of electrodes, EDLCs and theirtesting are described below.

Capacitor electrodes comprised 99 parts by weight carbon particles(average particle size 5-15 microns) and 1 part by weight Teflon. Thecarbon and Teflon were masticated in a mortar and pestle until theTeflon was well distributed and the composite had some physicalintegrity. After mixing, the composite was rolled out into a flat sheet,approximately 50 microns thick. Electrode disks, approximately 1.59 cmin diameter, were punched out of the sheet. The electrodes were placedin a vacuum oven attached to a dry box and heated for 12 hours at 195°C. This removed water adsorbed from the atmosphere during electrodepreparation. After drying, the electrodes were allowed to cool to roomtemperature, the atmosphere in the oven was filled with argon and theelectrodes were moved into the dry box where the capacitors were made.

A carbon electrode was placed into a cavity formed by a 1 inch (2.54 cm)diameter carbon-coated aluminum foil disk and a 50 micron thickpolyethylene gasket ring which had been heat sealed to the aluminum. Asecond electrode was then prepared in the same way. Two drops ofelectrolyte comprising 1.8 M tetraethylene ammonium tetrafluoroborate inacetonitrile were added to each electrode. Each electrode was coveredwith a 0.825 inch diameter porous polypropylene separator. The twoelectrode halves were sandwiched together with the separators facingeach other and the entire structure was hot pressed together.

When complete, the capacitor was ready for electrical testing with apotentiostat/function generator/frequency response analyzer. Capacitancewas measured by a constant current discharge method, comprising applyinga current pulse for a known duration and measuring the resulting voltageprofile. By choosing a given time and ending voltage, the capacitancewas calculated from the following C=It/ΔV, where C=capacitance,I=current, t=time to reached the desired voltage and ΔV=the voltagedifference between the initial and final voltages. The specificcapacitance based on the weight and volume of the two carbon electrodeswas obtained by dividing the capacitance by the weight and volumerespectively. This data is reported in Table 11 for discharge between2.7 and 1.89V.

The data in Table 2 shows that the carbons of this disclosuredemonstrate high power with improved volumetric capacitance over acommercially available carbon that was deemed not viable for market dueto its low density capacitance, but noted for its high turn on frequencycharacter—a character expanded by carbons of this disclosure to bothexhibit higher turn on frequency characteristics and higher volumetriccapacitance performance.

TABLE 2 Electrochemical Characteristics of Certain Carbon MaterialsGravimetric Volumetric Capacitance Capacitance Volumetric Gravimetric(F/g) (F/cc) Power Power Sample (@ 0.5 A/g) (@ 0.5 A/g) (W/cc) (W/g)Carbon 2 105-120 12-17 4-10  8-15 Carbon 3 115-125 10-14 6-10 15-30Commercial 105** 7.5 2 7.8 Carbon A** **Measured in 2.0 V (see Example10)

Carbon 2 was measured for stability testing at 2.7 voltage hold at 65°C. from zero to 128 hours. The higher stability nature of this carbon isdepicted in Table 3 as a high capacitance retention over stress testingcompared to two commercially available carbon materials (Commercialcarbons B and C) used as industry standard stable carbon in EDLCapplications. Carbon 4 is predominantly microporous carbon (see curvedenoted “NC2-1D” in FIG. 7).

TABLE 3 Electrochemical Stability as a function of % CapacitanceRetention over Time Capacitance % Retention of F/cc at 0.5 A/g, 2.7 Vhold at 65° C. after several time points (0-128 h) t = 0 h t = 24 h t =48 h t = 128 h Sample (%) (%) (%) (%) Carbon 2 100 89.9 87.5 82.2 Carbon4 100 84.6 79.3 68.3 Commercial 100 90.9 84.9 63.0 Carbon B Commercial100 89.3 85.4 75.3 Carbon C

Graphically, FIG. 4 shows that Carbon 2 exhibits higher stability at 128hours compared to carbons 4 and carbons B and C and extrapolation in thecharted trend points towards this carbon being a higher stability carbonthan other carbons in Table 3.

Resistance directly relates to power calculations. The lower theresistance, the higher the power performance. Resistance 1 refers todirect current discharge initial IR drop calculation. This is shown inFIGS. 5A and 5B for various carbon materials.

Stress testing showed that the resistances of Carbon 2 over time remainlow, which is a contrast to other carbons in Table 3. Low resistancedirectly relates to higher power performance.

A Bode plot (FIG. 6) was generated to depict the high frequency responseof typical of the disclosed carbon materials. In this plot, Carbon 2 isdesignated NC2-3. The shift to the right and higher frequency range onthe Bode plot indicates higher frequency response and power performance.

FIG. 7 shows how NC2-3 occupies a unique range of pore size distributioncompared to two comparator carbons.

Example 8 Electrochemical Properties of Other Carbon Samples

Another carbon sample (Carbon 2) was prepared according to the generalprocedures described in the Examples. EDLC coin cells comprising thecarbon material were prepared and their electrochemical propertiesanalyzed using 1M TEABF₄/ACN electrolyte. The results are tabulated inTables 4, 5 and 6 below.

TABLE 4 Capacitance and Current Density of Carbon 2 Current density 0.5A/g 1 A/g 4 A/g 8 A/g Capacitance 13.8 13.5 11.6 9.2 (F/cc) Capacitance113.1 110.4 94.7 75.6 (F/g)

Table 5 summarizes the resistance data for Carbon 2. Resistance 1 refersto direct current discharge initial IR drop calculation method.Resistance 2 refers to direct current discharge final voltage relaxationcalculation method. Resistance 3 refers to ESR taken at 2V EIS curve atreactance intercept which usually occurs near 400 kHz for the coincells.

TABLE 5 Resistance of the Carbon 2 Material Current density 0.5 A/g 1A/g 4 A/g 8 A/g Resistance 1 4.0 3.8 3.1 2.7 (ohm) Resistance 2 5.0 4.84.3 4.4 (ohm) Resistance 3 0.53 (ohm)

Table 6 summarizes the power data for EDLCs comprising the carbonmaterial. This power data is calculated from 2V EIS curve. Power numbercalculated from −45 deg phase angle.

TABLE 6 Power Data for the Carbon 2 Material Power density Power density(W/cc) (W/g) FOM Power value 5.0 10.3

Example 9 Properties of Other Carbon Samples

Additional carbon samples were prepared according to the generalprocedures described above.

TABLE 7 Electrochemical Data for the Carbon Materials GravimetricVolumetric Gravimetric Power Sample Capacitance (F/g) Capacitance (F/cc)(W/g) 5 118 12 57 6 127 11 61

TABLE 8 Physical Properties for the Carbon Materials Specific SurfaceTotal Pore Volume Sample Area (m²/g) (cc/g) 7 2113 2.03 8 1989 1.57

The pore size distribution of these carbon samples is shown in FIGS. 8and 9. FIG. 8 shows that two different batches of carbon materialexhibit similar pore structure, while FIG. 9 shows that the carbonmaterials according to the present disclosure comprise a high volume ofmesopore compared to other known carbon materials. Without being boundby theory, Applicants believe this mesoporosity contributes, at least inpart, to the enhanced electrochemical properties of the carbonmaterials.

Example 10 Properties and Performance of Capacitor Electrodes Comprisingthe Carbon Materials

A carbon material prepared according to the general procedures describedabove was evaluated for its properties and performance as an electrodein a symmetric electrochemical capacitor with a carbonate-based organicelectrolyte. A comprehensive set of property and performancemeasurements was performed on test capacitors fabricated with thismaterial.

The sample was very granular and included relatively large particles. Asa result, the capacitor's electrodes formed for the evaluation wereporous and had very low density (0.29 g/cm³). The electrode fabricatedusing the carbon material exhibited a high value of specific capacitance(105 F/g) but because of the very low electrode density the volumetriccapacitance was only 30 F/cc. Using the mass or volume of the dryelectrodes only, the test devices had Figure of Merit (FOM) values (seeMiller, “Pulse Power Performance of Electrochemical Capacitors:Technical Status of Present Commercial Devices,” Proc. 8th InternationalSeminar on Double Layer Capacitors and Similar Energy Storage Devices,Deerfield Beach, Fla. (Dec. 7-9, 1998)) around 7.8 W/g and 2 W/ml foroperation at 2 V. These values would be reduced by packaging withelectrolyte but increased by operation at higher voltages. Incomparison, the maximum reported FOM value for commercial capacitorproducts using organic electrolyte (1998) was 3.6 W/g and 4.1 W/ml. Thedisclosed carbon material compares very favorably to the commercialdevices on a weight basis, primarily because of the relatively high“turn-on” frequency (0.17 Hz). It is anticipated that the volumetricperformance of the carbon materials can be improved by reducing theparticle size by grinding or other processing.

The carbon sample was labeled 9AC16. The sample was dried at 60° C. thenmixed with a Teflon binder at 3.0% by weight. This mixture wasthoroughly blended and formed into 0.003″-thick-electrodes. The sampleappeared to have a significant fraction of larger particles which led toa porous and low density electrode. In some instances, 0.002″ thickelectrodes are used for evaluation but the sample could not be formedinto this thin a sheet with the integrity required for subsequenthandling, and thus, the thicker electrodes were prepared. The sheetmaterial was punched using a steel die to make discs 0.625″ in diameter.Four electrode discs of each material were weighed to an accuracy of 0.1mg. The average mass and density of a pair of electrodes is shown inTable 9.

TABLE 9 Electrode masses and volumes for test capacitors fabricatedusing the Carbon Materials. Combined Average mass thickness Volume oftwo of two of two Electrode electrodes electrodes electrodes Density ID(mg) (inches) (cm³) (g/cm³) 9AC16 8.7 0.006 0.003 0.29

The electrodes were dried under vacuum conditions (mechanical roughingpump) at 195° C. for 14 hours as the last preparation step.

After cooling, the vacuum container containing the electrodes (stillunder vacuum) was transferred into the drybox. All subsequent assemblywork was performed in the drybox. The electrode discs were soaked in theorganic electrolyte for 10 minutes then assembled into cells. Theelectrolyte was an equal volume mixture of propylene carbonate (PC) anddimethylcarbonate (DMC) that contained 1.0 M oftetraethylammoniumtetrafluoroborate (TEATFB) salt.

Two layers of an open cell foam type separator material were used toprepare the test cells. The double separator was ˜0.004″ thick before itis compressed in the test cell. Initially test cells were fabricatedusing the normal single layer of separator but these cells had highleakage currents, presumably because of particulates in the electrodespiercing the thin separator. The conductive faceplates of the test cellwere aluminum metal with a special surface treatment to preventoxidation (as used in the lithium-ion battery industry). Thethermoplastic edge seal material was selected for electrolytecompatibility and low moisture permeability and applied using an impulseheat sealer located directly within the drybox.

Two substantially identical test cells were fabricated. The assembledcells were removed from the drybox for testing. Metal plates wereclamped against each conductive face-plate and used as currentcollectors. The cross section of the assembled device is shown in FIG.10. The electrodes were each 0.003″ thick, and the separator 0.004″thick (a double layer of 0.002″ thick material). Electrodes had adiameter of 0.625″. Capacitor cells were conditioned at 1.0 V for tenminutes, measured for properties, then conditioned at 2.0 V for 10minutes and measured for properties.

The following test equipment was used for testing the capacitor cells:

1. Frequency Response Analyzer (FRA), Solartron model 1250Potentiostat/Galvanostat, PAR 273

2. Digital Multimeter, Keithley Model 197

3. Capacitance test box S/N 005, 500 ohm setting

4. RCL Meter, Philips PM6303 5. Power Supply, Hewlett-Packard ModelE3610A 6. Balance, Mettler H10 7. Micrometer, Brown/Sharp

8. Leakage current apparatus9. Battery/capacitor tester, Arbin Model EVTS

All measurements were performed at room temperature. The test capacitorswere conditioned at 1.0 V then shorted and the following measurementswere made: 1 kHz equivalent series resistance (ESR) using the RCL meter,charging capacitance at 1.0 V with a 500 ohm series resistance using thecapacitance test box, leakage current at 0.5 and 1.0 V after 30 minutesusing the leakage current apparatus, and electrochemical impedancespectroscopy (EIS) measurements using the electrochemical interface andFRA at 1.0 V bias voltage. Then the test capacitors were conditioned at2.0 V then shorted and the following measurements were made: 1 kHzequivalent series resistance (ESR) using the RCL meter, chargingcapacitance at 2.0 V with a 500 ohm series resistance, leakage currentat 1.5 and 2.0 V after 30 minutes using the leakage current apparatus,and EIS measurements at 2.0 V bias voltage. Finally charge/dischargemeasurements were made using the Arbin. These measurements includedconstant current charge/discharge cycles between 0.1 and 2.0 V atcurrents of 1, 5, and 15 mA and constant current charge/constant powerdischarges between 2.0 V and 0.5 V at power levels from 0.01 W to 0.2 W.

Tables 10 and 11 list test data for the capacitors fabricated withorganic electrolyte. The two samples are almost identical in theircharge storage properties, though they vary somewhat in density.

TABLE 10 Test results of two substantially identical prototypecapacitors constructed with the disclosed carbon materials. Testcapacitors #1 and #2 (data not shown) were fabricated with one layer ofseparator and were unsuitable for testing because of high leakagecurrents. 1 kHz 30 min leakage current ESR @ 1.0 V (μA) ID (Ω) C500 (F)0.5 V 1.0 V 9AC16 #3 3.457 0.21 1.7 7.4 9AC16 #4 3.558 0.20 5.1 15.0C500—500 Ω charging capacitance

TABLE 11 Test results after initial 1.0 V measurements of prototypecapacitors constructed with the disclosed carbon material. Specificcapacitance is on a dry-weight basis. 30 min 1 kHz leakage current ESR @2.0 V (μA) F/g F/cc ID (Ω) C500 (F) 1.5 V 2.0 V @ 2.0 V @ 2.0 V 9AC16 #33.296 0.23 11.8 53 106 30 9AC16 #4 3.522 0.22 23.7 70 102 29 C500—500 Ωcharging capacitance

FIG. 11 shows 30 minute leakage current values at four differentvoltages for the two test capacitors. A log-linear relationship betweenvoltage and leakage current is typical for electrochemical capacitorsand occurs when leakage current is dominated by charge transferreactions associated with impurities. The test capacitors exhibit closeto a log-linear relationship between leakage current and voltage. Thisrelationship is typical for electrochemical capacitors and occurs whenleakage current is charge transfer reactions associated with impurities.The leakage current values are within the normal range typicallymeasured for carbon electrode samples

FIG. 12 shows constant current discharge behavior of the capacitorscontaining the disclosed carbon materials when discharged at threecurrent values. The discharge rate at 5 mA corresponds to a currentdensity of ˜2.5 mA/cm².

FIG. 13a shows impedance data in a complex-plane representation for atest capacitor at voltages of 1.0 and 2.0 V. The behavior is verysimilar at both bias voltages. There is essentially no voltagedependence to the response, which is expected. An ideal RC circuit wouldbe represented by a straight vertical line that intersects the real axisat the value of the resistance. Shown is an intersection with the realaxis at ˜3.3Ω. The line rises for a short distance at an angle of −45degrees. This type behavior is seen in devices having porous electrodes,and may be due to distributed charge storage. After that the lines arenot quite vertical, which is usually due to a parallel charging pathsuch as a leakage current. Nevertheless, the non-ideal characteristicsare very minor for this sample.

FIG. 13b shows the same impedance data in a Bode representation, whichis the magnitude of the impedance |Z| and the phase angle versusfrequency. Capacitive behavior is evident by the −1 slope at lowerfrequencies and the phase angles approaching −90 degrees. Note the phaseangle is close to zero at high frequencies and approaches −90 degrees atlow frequencies.

FIG. 13c shows the same data in yet another representation—assuming thedevice can be represented by a series-RC circuit. The capacitance iscalculated as −1/(2πfZ″), where f is the frequency in Hz, Z″ is thereactance, and π=3.1415. As shown, the capacitance increases from aminimum at ˜200 Hz in a monotonic fashion as the frequency is reduced,reaching saturation of ˜0.24-0.25 F at frequencies below ˜0.1 Hz. Theseries resistance has a minimum value at about 1 kHz and increases asthe frequency is reduced. This type behavior is characteristic of aporous electrode, where the resistance increases at low frequencies ascharge storage occurs in deeper pores through longer paths ofelectrolyte.

The frequency at which a −45 degree phase angle is reached at 2.0 V biasis f_(o)˜0.17 Hz. The reactance Z″ (imaginary part of the impedance) atthis frequency is ˜−4.7Ω□ so the calculated capacitance at thisfrequency, assuming a series-RC circuit, is C=−1/(2πf_(o) Z″)=˜0.2 F.Thus at 2.0 V the calculated figure of merit (FOM) values described byMiller (“Pulse Power Performance of Electrochemical Capacitors:Technical Status of Present Commercial Devices,” Proc. 8th InternationalSeminar on Double Layer Capacitors and Similar Energy Storage Devices,Deerfield Beach, Fla. (Dec. 7-9, 1998)) are ˜7.8 W/g and ˜2.2 W/ml.Table 12 lists FOMs for the tested sample material. The larger the FOMvalues, the more suitable the material for pulse applications.

TABLE 12 Calculated gravimetric and volumetric Figure of Merit (FOM) ofthe disclosed carbon material in a test sample with organic electrolyteat a voltage of 2.0 V. Mass and volume include that of the two dryelectrodes only. Packaged devices are expected to have values reduced bytwo to four times, depending on product size. f₀ = −45 deg. Reactance C= 1/(2pi Gravimetric Volumetric freq. @ −450° ImZ Hz) E/M E/V FOM FOMSample (Hz) (Ω) (F) (J/g) (J/cc) ((W/g) (W/mL) 9AC16 #3 0.17 −4.70 0.20346.6 13.4 7.8 2.2

With electrolyte included, mass FOM will drop to about 4 W/g and thevolume value will remain unchanged. Packaging mass and volume impact tothe FOMs will be greatest for small devices. For instance, a furtherfour-fold reduction in the FOMs is expected for “button” size devices,while a two-fold reduction might result for hybrid vehicle sizecapacitor modules. FOM values of some commercial products are tabulatedin Table 13. The disclosed carbon material compares very favorably tothe commercial devices on a weight basis, primarily because of therelatively high “turn-on” frequency (0.17 Hz). It is expected that thevolumetric performance can be improved by reducing particle size bygrinding or other processing.

TABLE 13 FIGURE of Merit (FOM) of commercial electrochemical capacitorproducts at their rated voltages. (This data was obtained from small-and large- size commercial electrochemical capacitors in 1998, seeMiller.) E/M E/v Mass FOM Volume FOM EC PRODUCT (J/g) (J/cm³) (W/g)(W/cm³) Powerstor 1.3 1.9 2.1 3.0 Maxwell PC0323 6.2 6.9 1.0 1.1 MaxwellPC7223 9.7 12.8 0.5 0.64 Maxwell PC0223 4.5 9.9 0.5 1.1 cap-XX card0.047 0.062 1.3 1.7 cap-XX 120 F 7.4 7.0 0.74 0.7 cap-XX 30 F 1.3 1.32.7 2.7 cap-XX 10 F 0.54 0.61 3.6 4.1 cap-XX 250 F 2.2 1.6 2.2 1.6 ELNA4.4 5.0 0.36 0.4 Panasonic 6.7 7.2 0.34 0.37 ELIT 9.4 F 0.093 0.31 0.953.2 ESMA 2.2 4.3 0.22 0.43 Powercell 7.3 10 0.07 0.09 ELIT 20 kJ 1.2 2.70.2 0.46 ECOND 8/16/0.8 0.68 2.1 0.09 0.27 ECOND 8/16/10 0.51 1.7 0.431.4

Another way of showing the performance of a capacitor is by showing theenergy-power relationship in the Ragone representation as shown in FIG.14. The energy that can be delivered decreases as the power increases.The energy and power values shown in the figure were determinedexperimentally with constant power discharges from 2.0 V to 0.5 V.Comparison to commercial devices is difficult because of the unknownsassociated with packaging mass and volume and because commercial organicelectrolyte capacitors often use acetonitrile and operate at highervoltages.

Example 11 Comparison of Different Methods for Preparing the CarbonMaterials

A comparison of different methods for preparation of carbon materialswas performed by preparing polymer gels as described above and eitherflash freezing in liquid nitrogen as described above or freezing moreslowly on a freezer shelf. The studies indicate that flash freezingresults in a carbon material having higher mesoporosity and superiorelectrochemical properties. The freeze drying, pyrolysis and activationconditions were as follows:

The polymer gel was ground with a mechanical grater using a 2 mm grinderfitting. The polymer gel was then flash frozen with liquid N₂ and shelffrozen at −50° C. After flash freezing, the polymer gel was freeze driedaccording to the following protocol:

-   -   1. Hold at −50° C. and 50 mTorr;    -   2. Ramp from −50° C. to −30° C. in 30 mins at 50 mTorr;    -   3. Ramp from −30° C. to +25° C. in 220 mins at 50 mTorr; and    -   4. Continual ‘hold’ at +25° C. and 50 mTorr.

After freeze drying, the polymer gel was pyrolyzed in a tube furnace byramping the temperature up by 5° C. per minute under N₂ gas to 900° C.,dwelling at 900° C. for 60 minutes under N₂ gas and then ramping down toambient temperature under N₂ gas. The pyrolyzed material was thenactivated in a tube furnace to a target weight loss. The activationparameters can be adjusted to obtain the desired activation result.

Table 14 summarizes dried gel and pyrolyzed carbon characterization fromthese two methods.

TABLE 14 Dried Gel and Pyrolyzed Carbon Characteristics Based onPreparation Method Total Weight Pore Tap Process Loss SSA Volume DensitySample # Conditions (%) (m²/g) (cc/g) (g/cc) RD-111-1-DG Freezing Method73.4 753 1.40 0.22 Liq N₂ RD-111-2-DG Freezing Method 73.1 578 0.43 0.45Shelf Freeze RD-111-1-PC Pyrolysis 50.5 786 0.94 0.32 60 mins @ 900° C.RD-111-2-PC Pyrolysis 49.7 664 0.33 0.56 60 mins @ 900° C. Dried GelFreezing Method 66.2 609 0.58 0.43 Control Liq N₂ (control chart values)

FIG. 15 shows that flash frozen polymer gels comprise highermesoporosity than gels frozen more slowly. The pore size distribution(PSD) trend in the dried gel directly translated to PSD in the activatedcarbon as depicted in Table 14 and FIG. 16. For example, the flashfrozen dried gel also produced activated carbon with high total porevolume (+2.0 cc/g) and lower tap density than the shelf frozen driedgel.

Liquid nitrogen and shelf frozen dried gels had very similar activationweight loss per time at temperature, but produced very different surfacearea activated carbons. From Table 2, for the same lower and higheractivation parameters, similar weight losses were achieved but differentSSA was measured. For example, RD-111-1-AC4 and RD-111-2-AC2 wereactivated for 74 mins at 950° C. and achieved 55.5% and 52.2% weightloss respectively. The same was found at the lower activation settingsof 55 mins at 950° C. (39.8% and 38.5%). However, for the given weightlosses, different specific surface areas were attained, FIG. 17.

The carbon materials prepared by slow freezing had lower powerperformance. While not wishing to be bound by theory, Applicants believethis low power performance can be attributed to the lack of mesopores inthese carbon materials. It is also believed that this lack ofmesoporosity contributes to the higher tap densities and lower totalpoor volume of these carbon materials as shown in Table 15

TABLE 15 Properties of Activated Carbons Total Activation Pore TapFreezing Activation Wt loss Volume Density Sample # Method Conditions(%) SSA (m²/g) (cc/g) (g/cc) RD-111-1-AC1 Liq. N₂ 10 mins @ 1 — — — 800°C. RD-111-1-AC2 Liq. N₂ 18 mins @ 1.2 — — — 800° C. RD-111-1-AC3 Liq. N₂55 mins @ 39.8 2114 2.06 0.24 950° C. RD-111-1-AC4 Liq. N₂ 74 mins @55.5 2684 2.50 0.17 950° C. RD-111-2-AC1 Shelf 55 mins @ 38.5 1310 0.630.41 Freeze 950° C. RD-111-2-AC2 Shelf 74 mins @ 52.2 1583 0.77 0.36Freeze 950° C.

Example 12 Alternative Preparation of a Carbon Material

A carbon material (“Carbon 9”) useful in lead acid battery applications(among others) was prepared according to the following description. Apolymer gel was prepared by polymerization of resorcinol andformaldehyde (0.5:1) in a water/acetic acid solvent (80:20) in thepresence of ammonium acetate catalyst. The resultant polymer to solventratio was 0.3, and the resorcinol to catalyst ratio (R/C) was 25. Thereaction mixture was placed at elevated temperature (incubation at 45°C. for about 6 h followed by incubation at 85° C. for about 24 h) toallow for gellation to create a polymer gel. Polymer gel particles werecreated from the polymer gel with a rock crusher through a screen with ¾inch sized holes. The particles were flash frozen by immersion in liquidnitrogen, loaded into a lyophilization tray at a loading of 3 to 7g/in², and lyophilized at approximately 50 to 150 mTorr. The time to dry(as inferred from time for product to reach within 2° C. of shelftemperature) varied with product loading on the lyophilizer shelf.

The mass loss on drying the polymer gel was approximately 72%. Thesurface area of the dried polymer gel was determined to be 691 m²/g, thetotal pore volume was 1.05 cc/g and the tap density was 0.32 g/cc. Driedpolymer gel materials comprising different properties (e.g., surfacearea, pore structure, etc.) can be prepared by altering the dryingconditions (e.g., pressure, temperature, time, etc.) described above.

Dried polymer gel prepared according was pyrolyzed by passage into arotary kiln at 900° C. with a nitrogen gas flow of 200 L/h. The surfacearea of the pyrolyzed dried polymer gel was examined by nitrogen surfaceanalysis using a surface area and porosity analyzer. The measuredspecific surface area using the standard BET approach was 737 m²/g, thetotal pore volume was 0.64 cc/g. Carbon materials comprising differentproperties (e.g., surface area, pore structure, etc.) can be prepared byaltering the pyrolysis conditions (e.g., temperature, time, etc.)described above.

FIG. 18 shows an overlay of the pore size distributions of variouscarbon materials. Note that the pore size distribution for the activatedcarbon was measured on a micromeritics ASAP2020, a micropore-capableanalyzer with a higher resolution (lower pore size volume detection)than the Tristar 3020 that was used to measure the pore sizedistribution for the dried polymer gel.

From the DFT cumulative volume plot for the activated carbon material,it was determined that about 40% of the pore volume resides inmicropores and about 60% of the pore volume resides in mesopores. Carbonmaterials comprising different properties (e.g., surface area, porestructure, etc.) can be prepared by altering the activation conditions(e.g., temperature, time, etc.) described above.

Pyrolyzed carbon prepared was jet milled using a manufacturing scale 15inch diameter jet mill. The average particle size after jet milling wasabout 4 to 7 microns. Properties of Carbon 1 are summarized in Table 16.Table 17 summarizes the range of properties of various carbonembodiments prepared according the above procedures.

TABLE 16 Physiochemical Properties of Carbon 1 Test Parameter Result TapDensity Tap Density (g/cc) 0.43 N2 Sorption Isotherm Specific SurfaceArea (m²/g) 737 Total pore volume (cc/g) 0.64 DFT Pore volume >20 Å(cc/g) 0.38 N₂ (p/p0)₉₅/(p/po)₅: 2.0-2.7 2.2 (i.e., “P95/P5”) ThermalGravimetric % weight loss observed between 1.0 Analysis (TGA) 250 to 850C. Ash Content Calculated from PIXE elemental 0.0008 data (%) PIXEPurity Sulfur (ppm): ND Silicon (ppm): ND Calcium (ppm): ND Iron (ppm):6.2 Nickel ppm): 1.1 Zinc (ppm): ND Copper (ppm): ND Chromium (ppm): NDAll other elements: ND ND = not detected

Example 13 Alternative Preparation of a Carbon Material

A carbon material (“Carbon 12”) having increased energy density withbalanced power performance was prepared according to the followingdescription. A polymer gel was prepared by polymerization of resorcinoland formaldehyde (0.5:1) in a water/acetic acid solvent (80:20) in thepresence of ammonium acetate catalyst. The resultant polymer to solventratio was 0.3, and the resorcinol to catalyst ratio (R/C) was 25. Thereaction mixture was placed at elevated temperature (incubation at 45°C. for about 6 h followed by incubation at 85° C. for about 24 h) toallow for gellation to create a polymer gel. Polymer gel particles werecreated from the polymer gel with a rock crusher through a screen with ¾inch sized holes. The particles were loaded into a lyophilization trayat a loading of 3 to 7 g/in², frozen on the shelf of a freeze-dryeruntil particles were frozen below −30° C. The frozen particles werelyophilized at approximately 50 mTorr. The time to dry (as inferred fromtime for product to reach within 2° C. of shelf temperature) varied withproduct loading on the lyophilizer shelf. At manufacturing scale,polymer gel particles were loaded on lyophilization trays in a −30° C.cold room and frozen over the course of 24 hours. These frozen particleswere lyophilized at approximately 120 mTorr. The time to dry (asinferred from time for product to reach within 2° C. of shelftemperature) varied with product loading on the lyophilizer shelf.

The mass loss on drying the polymer gel was 74.1%. The surface area ofthe dried polymer gel was determined to be 515 m²/g, the total porevolume was 0.39 cc/g and the tap density was 0.22 g/cc. The pore sizedistribution of two different batches of dried polymer gel is shown inFIG. 19 that exhibit a range of physical properties from altering thelyophilization parameters.

Dried polymer gel prepared according to the above procedure waspyrolyzed by passage into a furnace at 625° C. with a nitrogen gas flowof 400 L/h. At manufacturing scale, dried polymer gel prepared accordingto the above procedure was pyrolyzed by passage into a rotating kilnfurnace set with three hot zones of 685° C., 750° C., and 850° C.

The surface area of the pyrolyzed dried polymer gel pyrolyzed by passageinto a furnace at 625° C. was examined by nitrogen surface analysisusing a surface area and porosity analyzer. The measured specificsurface area using the standard BET approach was 622 m²/g, the totalpore volume was 0.33 cc/g. The surface area of the pyrolyzed driedpolymer gel pyrolyzed by passage into a rotary kiln furnace set withthree hot zones of 685° C., 750° C., and 850° C. was examined bynitrogen surface analysis using a surface area and porosity analyzer.The measured specific surface area using the standard BET approach was588 m²/g, the total pore volume was 0.25 cc/g. Carbon materialscomprising different properties (e.g., surface area, pore structure,etc.) can be prepared by altering the pyrolysis conditions (e.g.,temperature, time, etc.) described above.

Pyrolyzed carbon material prepared according to above was activated in abatch rotary kiln at 900° C. under CO₂ for approximately 840 min,resulting in a total weight loss of 50%. In another case, Pyrolyzedcarbon material prepared according to above was activated in a fluidizedbed reactor at 925° C. under CO₂.

The surface area of the activated carbon produced by a batch rotary kilnas described above was examined by nitrogen surface analysis using asurface area and porosity analyzer. The measured specific surface areausing the BET approach was 1857 m²/g, the total pore volume was 0.87cc/g and the tap density was 0.41 g/cc. In the second case using afluidized bed reactor, the resultant material was also measured bynitrogen adsorption analysis and the measured specific surface areausing the BET approach was 2046 m²/g, and the total pore volume was 1.03cc/g.

FIG. 20 shows an example of the pore size distributions of the activatedcarbon material from both the activation conditions described above.Note that the pore size distribution for the activated carbon wasmeasured on a micromeritics ASAP2020, a micropore-capable analyzer witha higher resolution (lower pore size volume detection) than the Tristar3020 that was used to measure the pore size distribution for the driedpolymer gel.

From the DFT cumulative volume plot for the activated carbon material,it was determined that the 80% of the pore volume resides in microporesand 20% of the pore volume resides in mesopores. In the second case ofactivated carbon materials depicted in FIG. 20, it was determined that70% of the pore volume resides in the micropores and 30% of the porevolume resides in the mesopores. Carbon materials comprising differentproperties (e.g., surface area, pore structure, etc.) can be prepared byaltering the activation conditions (e.g., temperature, time, etc.)described above.

Activated carbon prepared was jet milled using a Jet Pulverizer MicronMaster 2 inch diameter jet mill and at the manufacturing scale, a 15inch diameter jet mill was used. The average particle size after jetmilling was about 4 to 7 microns.

Chemical species on the surface of the activated carbon was removed witha heat treatment process by heating the carbon in an elevator furnaceunder nitrogen gas for 1 hour at 900° C. The pH was measured on thetreated carbon and was 7.9 indicating a lack of oxygen containingsurface functional groups. Properties of various carbons prepared by theabove method are summarized in Table 18.

Example 14 Alternative Preparation of a Carbon Material

A carbon material (“Carbon 13”) having increased energy density withbalanced power performance was prepared according to the followingdescription. A polymer gel was prepared by polymerization of resorcinoland formaldehyde (0.5:1) in a water/acetic acid solvent (80:20) in thepresence of ammonium acetate catalyst. The resultant polymer to solventratio was 0.3, and the resorcinol to catalyst ratio (R/C) was 25. Thereaction mixture was placed at elevated temperature (incubation at 45°C. for about 6 h followed by incubation at 85° C. for about 24 h) toallow for gellation to create a polymer gel. Polymer gel particles werecreated from the polymer gel with a rock crusher through a screen with ¾inch sized holes.

Polymer gel particles were prepared was pyrolyzed by passage into afurnace at 625° C. with a nitrogen gas flow of 400 L/h.

The surface area of the pyrolyzed dried polymer gel was examined bynitrogen surface analysis using a surface area and porosity analyzer.The measured specific surface area using the standard BET approach was585 m²/g, the total pore volume was 0.28 cc/g. Carbon materialscomprising different properties (e.g., surface area, pore structure,etc.) can be prepared by altering the pyrolysis conditions (e.g.,temperature, time, etc.) described above.

Pyrolyzed carbon material prepared according to above was activated in a4″ Fluidized Bed Reactor at 900° C. under a CO₂ for approximately 15hours.

The surface area of the activated carbon was examined by nitrogensurface analysis using a surface area and porosity analyzer. Themeasured specific surface area using the BET approach was 2529 m²/g, thetotal pore volume was 1.15 cc/g and the tap density was 0.36 g/cc.

From the DFT cumulative volume plot for the activated carbon material,it was determined that the 68% of the pore volume resides in microporesand 32% of the pore volume resides in mesopores. Carbon materialscomprising different properties (e.g., surface area, pore structure,etc.) can be prepared by altering the activation conditions (e.g.,temperature, time, etc.) described above.

Activated carbon prepared was jet milled using a Jet Pulverizer MicronMaster 2 inch diameter jet mill. The average particle size after jetmilling was about 4 to 7 microns.

Example 15 Properties of Various Carbon Materials

Carbon materials having various properties can be prepared according tothe general procedures described above. Table 17 summarizes theproperties of carbon materials prepared according to the noted examples.

TABLE 17 Physiochemical Characteristics of Carbons Prepared According toExamples 2-14 Ratio N₂ PV meso/ Total Pore Tap adsorbed PV SSA VolumeDensity (P/Po)95/(P/ total Example (m²/g) (cc/g) (g/cc) Po)5 (%) PurityEx. 12 600-800 0.5-0.9 0.35-0.45 2.0-3.0 40-60% <200 ppm impurities Ash:0.001-0.03% Ex. 1-3 1550-2100 1.2-1.6 0.25-0.35 1.8-2.5 52-60% <200 ppmimpurities Ash: 0.001-0.03% Ex. 1-3 2100-2800 1.5-2.7 0.19-0.28 2.0-2.552-60% <200 ppm impurities Ash: 0.001-0.03% Ex. 13 1800-2200 0.8-1.20.30-0.45 1.2-1.6 20-50% <200 ppm impurities Ash: 0.001-0.03% Ex. 141800-2600 0.7-1.3 0.25-0.45 1.2-1.8 20-50% <200 ppm impurities Ash:0.001-0.03%

The various embodiments described above can be combined to providefurther embodiments. All of the U.S. patents, U.S. patent applicationpublications, U.S. patent applications, foreign patents, foreign patentapplications and non-patent publications referred to in thisspecification and/or listed in the Application Data Sheet, areincorporated herein by reference, in their entirety. Aspects of theembodiments can be modified, if necessary to employ concepts of thevarious patents, applications and publications to provide yet furtherembodiments. These and other changes can be made to the embodiments inlight of the above-detailed description. In general, in the followingclaims, the terms used should not be construed to limit the claims tothe specific embodiments disclosed in the specification and the claims,but should be construed to include all possible embodiments along withthe full scope of equivalents to which such claims are entitled.Accordingly, the claims are not limited by the disclosure.

1-75. (canceled)
 76. A carbon material comprising a pore structure, thepore structure comprising micropores, mesopores and a total pore volume,wherein from 20% to 50% of the total pore volume resides in micropores,from 50% to 80% of the total pore volume resides in mesopores and lessthan 10% of the total pore volume resides in pores greater than 20 nm.77. The carbon material of claim 76, wherein from 20% to 40% of thetotal pore volume resides in micropores and from 60% to 80% of the totalpore volume resides in mesopores.
 78. The carbon material of claim 76,wherein from 25% to 35% of the total pore volume resides in microporesand from 65% to 75% of the total pore volume resides in mesopores. 79.The carbon material of claim 76, wherein about 30% of the total porevolume resides in micropores and about 70% of the total pore volumeresides in mesopores.
 80. The carbon material of claim 76, wherein from30% to 50% of the total pore volume resides in micropores and from 50%to 70% of the total pore volume resides in mesopores.
 81. The carbonmaterial of claim 76, wherein from 35% to 45% of the total pore volumeresides in micropores and from 55% to 65% of the total pore volumeresides in mesopores.
 82. The carbon material of claim 76, wherein about40% of the total pore volume resides in micropores and about 60% of thetotal pore volume resides in mesopores.
 83. The carbon material of claim76, wherein less than 5% of the total pore volume resides in poresgreater than 20 nm.
 84. The carbon material of claim 76, wherein thecarbon material comprises a BET specific surface area of at least 300m²/g.
 85. The carbon material of claim 76, wherein the carbon materialcomprises a BET specific surface area of at least 500 m²/g.
 86. Thecarbon material of claim 76, wherein the carbon material comprises apore volume of at least 0.50 cc/g.
 87. The carbon material of claim 76,wherein the carbon material comprises a pore volume of at least 0.60cc/g.
 88. The carbon material of claim 76, wherein the carbon materialcomprises a pore volume of at least 0.70 cc/g.
 89. An electrodecomprising the carbon material of claim
 76. 90. A device comprising thecarbon material of claim
 76. 91. The device of claim 90, wherein thedevice is an EDLC, lithium/carbon battery, zinc/carbon, lithium airbattery or lead acid battery.
 92. The device of claim 90, wherein thedevice is a lead/acid battery comprising: a) at least one positiveelectrode comprising a first active material in electrical contact witha first current collector; b) at least one negative electrode comprisinga second active material in electrical contact with a second currentcollector; and c) an electrolyte; wherein the positive electrode and thenegative electrode are separated by an inert porous separator, andwherein at least one of the first or second active materials comprisesthe carbon material.